From a3d66bd89f9622c6213589b98f7e98b425da58cb Mon Sep 17 00:00:00 2001
From: Daniel Noel-Davies <daniel.noel-davies@endclothing.com>
Date: Fri, 19 Jul 2019 11:31:19 +0100
Subject: [PATCH 01/28] Replace PHPUnit v with PHPUnit 7

---
 composer.json                                 |  4 ++--
 examples/pushgateway.php                      |  3 ++-
 src/Prometheus/Collector.php                  |  7 ++++---
 .../Exception/MetricNotFoundException.php     |  4 +++-
 .../MetricsRegistrationException.php          |  4 +++-
 src/Prometheus/Exception/StorageException.php |  4 +++-
 src/Prometheus/Histogram.php                  |  7 ++++---
 src/Prometheus/PushGateway.php                |  7 ++++---
 src/Prometheus/Storage/APC.php                | 13 +++++++------
 src/Prometheus/Storage/Redis.php              |  9 +++++++--
 tests/Test/BlackBoxPushGatewayTest.php        |  3 ++-
 tests/Test/BlackBoxTest.php                   |  4 ++--
 .../AbstractCollectorRegistryTest.php         | 19 ++++++++++---------
 tests/Test/Prometheus/AbstractCounterTest.php |  9 +++++----
 tests/Test/Prometheus/AbstractGaugeTest.php   |  9 +++++----
 .../Test/Prometheus/AbstractHistogramTest.php | 15 ++++++++-------
 tests/Test/Prometheus/Storage/RedisTest.php   | 10 ++++++----
 17 files changed, 77 insertions(+), 54 deletions(-)

diff --git a/composer.json b/composer.json
index b941542..ef6c2cf 100644
--- a/composer.json
+++ b/composer.json
@@ -16,14 +16,14 @@
         "symfony/polyfill-apcu": "^1.6"
     },
     "require-dev": {
-        "phpunit/phpunit": "4.1.0"
+        "phpunit/phpunit": "^7.5"
     },
     "suggest": {
         "ext-redis": "Required if using Redis.",
         "ext-apc": "Required if using APCu."
     },
     "autoload": {
-        "psr-0": {
+        "psr-4": {
             "Prometheus\\": "src/"
         }
     },
diff --git a/examples/pushgateway.php b/examples/pushgateway.php
index 984035d..feb2172 100644
--- a/examples/pushgateway.php
+++ b/examples/pushgateway.php
@@ -1,6 +1,7 @@
 <?php
 require __DIR__ . '/../vendor/autoload.php';
 
+use Prometheus\PushGateway;
 use Prometheus\Storage\Redis;
 use Prometheus\CollectorRegistry;
 
@@ -20,5 +21,5 @@
 $counter = $registry->registerCounter('test', 'some_counter', 'it increases', ['type']);
 $counter->incBy(6, ['blue']);
 
-$pushGateway = new \Prometheus\PushGateway('192.168.59.100:9091');
+$pushGateway = new PushGateway('192.168.59.100:9091');
 $pushGateway->push($registry, 'my_job', array('instance'=>'foo'));
diff --git a/src/Prometheus/Collector.php b/src/Prometheus/Collector.php
index edc5e80..2b77554 100644
--- a/src/Prometheus/Collector.php
+++ b/src/Prometheus/Collector.php
@@ -3,6 +3,7 @@
 namespace Prometheus;
 
 
+use InvalidArgumentException;
 use Prometheus\Storage\Adapter;
 
 abstract class Collector
@@ -26,13 +27,13 @@ public function __construct(Adapter $storageAdapter, $namespace, $name, $help, $
         $this->storageAdapter = $storageAdapter;
         $metricName = ($namespace ? $namespace . '_' : '') . $name;
         if (!preg_match(self::RE_METRIC_LABEL_NAME, $metricName)) {
-            throw new \InvalidArgumentException("Invalid metric name: '" . $metricName . "'");
+            throw new InvalidArgumentException("Invalid metric name: '" . $metricName . "'");
         }
         $this->name = $metricName;
         $this->help = $help;
         foreach ($labels as $label) {
             if (!preg_match(self::RE_METRIC_LABEL_NAME, $label)) {
-                throw new \InvalidArgumentException("Invalid label name: '" . $label . "'");
+                throw new InvalidArgumentException("Invalid label name: '" . $label . "'");
             }
         }
         $this->labels = $labels;
@@ -69,7 +70,7 @@ public function getKey()
     protected function assertLabelsAreDefinedCorrectly($labels)
     {
         if (count($labels) != count($this->labels)) {
-            throw new \InvalidArgumentException(sprintf('Labels are not defined correctly: ', print_r($labels, true)));
+            throw new InvalidArgumentException(sprintf('Labels are not defined correctly: ', print_r($labels, true)));
         }
     }
 }
diff --git a/src/Prometheus/Exception/MetricNotFoundException.php b/src/Prometheus/Exception/MetricNotFoundException.php
index ff67175..d35533f 100644
--- a/src/Prometheus/Exception/MetricNotFoundException.php
+++ b/src/Prometheus/Exception/MetricNotFoundException.php
@@ -4,10 +4,12 @@
 namespace Prometheus\Exception;
 
 
+use Exception;
+
 /**
  * Exception thrown if a metric can't be found in the CollectorRegistry.
  */
-class MetricNotFoundException extends \Exception
+class MetricNotFoundException extends Exception
 {
 
 }
diff --git a/src/Prometheus/Exception/MetricsRegistrationException.php b/src/Prometheus/Exception/MetricsRegistrationException.php
index 17f70be..673ad0b 100644
--- a/src/Prometheus/Exception/MetricsRegistrationException.php
+++ b/src/Prometheus/Exception/MetricsRegistrationException.php
@@ -4,10 +4,12 @@
 namespace Prometheus\Exception;
 
 
+use Exception;
+
 /**
  * Exception thrown if an error occurs during metrics registration.
  */
-class MetricsRegistrationException extends \Exception
+class MetricsRegistrationException extends Exception
 {
 
 }
diff --git a/src/Prometheus/Exception/StorageException.php b/src/Prometheus/Exception/StorageException.php
index 782e6e3..641a739 100644
--- a/src/Prometheus/Exception/StorageException.php
+++ b/src/Prometheus/Exception/StorageException.php
@@ -4,10 +4,12 @@
 namespace Prometheus\Exception;
 
 
+use Exception;
+
 /**
  * Exception thrown if an error occurs during metrics storage.
  */
-class StorageException extends \Exception
+class StorageException extends Exception
 {
 
 }
diff --git a/src/Prometheus/Histogram.php b/src/Prometheus/Histogram.php
index 9dbfda4..cafbcbe 100644
--- a/src/Prometheus/Histogram.php
+++ b/src/Prometheus/Histogram.php
@@ -3,6 +3,7 @@
 namespace Prometheus;
 
 
+use InvalidArgumentException;
 use Prometheus\Storage\Adapter;
 
 class Histogram extends Collector
@@ -28,12 +29,12 @@ public function __construct(Adapter $adapter, $namespace, $name, $help, $labels
         }
 
         if (0 == count($buckets)) {
-            throw new \InvalidArgumentException("Histogram must have at least one bucket.");
+            throw new InvalidArgumentException("Histogram must have at least one bucket.");
         }
 
         for ($i = 0; $i < count($buckets) - 1; $i++) {
             if ($buckets[$i] >= $buckets[$i + 1]) {
-                throw new \InvalidArgumentException(
+                throw new InvalidArgumentException(
                     "Histogram buckets must be in increasing order: " .
                     $buckets[$i] . " >= " . $buckets[$i + 1]
                 );
@@ -41,7 +42,7 @@ public function __construct(Adapter $adapter, $namespace, $name, $help, $labels
         }
         foreach ($labels as $label) {
             if ($label === 'le') {
-                throw new \InvalidArgumentException("Histogram cannot have a label named 'le'.");
+                throw new InvalidArgumentException("Histogram cannot have a label named 'le'.");
             }
         }
         $this->buckets = $buckets;
diff --git a/src/Prometheus/PushGateway.php b/src/Prometheus/PushGateway.php
index a4a3fd2..42f3197 100644
--- a/src/Prometheus/PushGateway.php
+++ b/src/Prometheus/PushGateway.php
@@ -5,6 +5,7 @@
 
 
 use GuzzleHttp\Client;
+use RuntimeException;
 
 class PushGateway
 {
@@ -44,7 +45,7 @@ public function pushAdd(CollectorRegistry $collectorRegistry, $job, $groupingKey
     }
 
     /**
-     * Deletes metrics from the Pushgateway.
+     * Deletes metrics from the Push Gateway.
      * Uses HTTP POST.
      * @param $job
      * @param $groupingKey
@@ -83,8 +84,8 @@ private function doRequest(CollectorRegistry $collectorRegistry, $job, $grouping
         $response = $client->request($method, $url, $requestOptions);
         $statusCode = $response->getStatusCode();
         if ($statusCode != 202) {
-            $msg = "Unexpected status code " . $statusCode . " received from pushgateway " . $this->address . ": " . $response->getBody();
-            throw new \RuntimeException($msg);
+            $msg = "Unexpected status code " . $statusCode . " received from push gateway " . $this->address . ": " . $response->getBody();
+            throw new RuntimeException($msg);
         }
     }
 
diff --git a/src/Prometheus/Storage/APC.php b/src/Prometheus/Storage/APC.php
index b608e49..3d386fa 100644
--- a/src/Prometheus/Storage/APC.php
+++ b/src/Prometheus/Storage/APC.php
@@ -4,6 +4,7 @@
 namespace Prometheus\Storage;
 
 
+use APCUIterator;
 use Prometheus\MetricFamilySamples;
 use RuntimeException;
 
@@ -148,7 +149,7 @@ private function metaData(array $data)
     private function collectCounters()
     {
         $counters = array();
-        foreach (new \APCUIterator('/^prom:counter:.*:meta/') as $counter) {
+        foreach (new APCUIterator('/^prom:counter:.*:meta/') as $counter) {
             $metaData = json_decode($counter['value'], true);
             $data = array(
                 'name' => $metaData['name'],
@@ -156,7 +157,7 @@ private function collectCounters()
                 'type' => $metaData['type'],
                 'labelNames' => $metaData['labelNames'],
             );
-            foreach (new \APCUIterator('/^prom:counter:' . $metaData['name'] . ':.*:value/') as $value) {
+            foreach (new APCUIterator('/^prom:counter:' . $metaData['name'] . ':.*:value/') as $value) {
                 $parts = explode(':', $value['key']);
                 $labelValues = $parts[3];
                 $data['samples'][] = array(
@@ -178,7 +179,7 @@ private function collectCounters()
     private function collectGauges()
     {
         $gauges = array();
-        foreach (new \APCUIterator('/^prom:gauge:.*:meta/') as $gauge) {
+        foreach (new APCUIterator('/^prom:gauge:.*:meta/') as $gauge) {
             $metaData = json_decode($gauge['value'], true);
             $data = array(
                 'name' => $metaData['name'],
@@ -186,7 +187,7 @@ private function collectGauges()
                 'type' => $metaData['type'],
                 'labelNames' => $metaData['labelNames'],
             );
-            foreach (new \APCUIterator('/^prom:gauge:' . $metaData['name'] . ':.*:value/') as $value) {
+            foreach (new APCUIterator('/^prom:gauge:' . $metaData['name'] . ':.*:value/') as $value) {
                 $parts = explode(':', $value['key']);
                 $labelValues = $parts[3];
                 $data['samples'][] = array(
@@ -209,7 +210,7 @@ private function collectGauges()
     private function collectHistograms()
     {
         $histograms = array();
-        foreach (new \APCUIterator('/^prom:histogram:.*:meta/') as $histogram) {
+        foreach (new APCUIterator('/^prom:histogram:.*:meta/') as $histogram) {
             $metaData = json_decode($histogram['value'], true);
             $data = array(
                 'name' => $metaData['name'],
@@ -223,7 +224,7 @@ private function collectHistograms()
             $data['buckets'][] = '+Inf';
 
             $histogramBuckets = array();
-            foreach (new \APCUIterator('/^prom:histogram:' . $metaData['name'] . ':.*:value/') as $value) {
+            foreach (new APCUIterator('/^prom:histogram:' . $metaData['name'] . ':.*:value/') as $value) {
                 $parts = explode(':', $value['key']);
                 $labelValues = $parts[3];
                 $bucket = $parts[4];
diff --git a/src/Prometheus/Storage/Redis.php b/src/Prometheus/Storage/Redis.php
index 091577c..a099cd1 100644
--- a/src/Prometheus/Storage/Redis.php
+++ b/src/Prometheus/Storage/Redis.php
@@ -3,11 +3,13 @@
 namespace Prometheus\Storage;
 
 
+use InvalidArgumentException;
 use Prometheus\Counter;
 use Prometheus\Exception\StorageException;
 use Prometheus\Gauge;
 use Prometheus\Histogram;
 use Prometheus\MetricFamilySamples;
+use RedisException;
 
 class Redis implements Adapter
 {
@@ -59,6 +61,9 @@ public static function setPrefix($prefix)
         self::$prefix = $prefix;
     }
 
+    /**
+     * @throws StorageException
+     */
     public function flushRedis()
     {
         $this->openConnection();
@@ -103,7 +108,7 @@ private function openConnection()
 
             $this->redis->setOption(\Redis::OPT_READ_TIMEOUT, $this->options['read_timeout']);
             
-        } catch (\RedisException $e) {
+        } catch (RedisException $e) {
             throw new StorageException("Can't connect to Redis server", 0, $e);
         }
     }
@@ -342,7 +347,7 @@ private function getRedisCommand($cmd)
             case Adapter::COMMAND_SET:
                 return 'hSet';
             default:
-                throw new \InvalidArgumentException("Unknown command");
+                throw new InvalidArgumentException("Unknown command");
         }
     }
 
diff --git a/tests/Test/BlackBoxPushGatewayTest.php b/tests/Test/BlackBoxPushGatewayTest.php
index 26490c6..5453f43 100644
--- a/tests/Test/BlackBoxPushGatewayTest.php
+++ b/tests/Test/BlackBoxPushGatewayTest.php
@@ -2,13 +2,14 @@
 namespace Test;
 
 use GuzzleHttp\Client;
+use PHPUnit\Framework\TestCase;
 use PHPUnit_Framework_TestCase;
 
 use Prometheus\CollectorRegistry;
 use Prometheus\PushGateway;
 use Prometheus\Storage\APC;
 
-class BlackBoxPushGatewayTest extends PHPUnit_Framework_TestCase
+class BlackBoxPushGatewayTest extends TestCase
 {
     /**
      * @test
diff --git a/tests/Test/BlackBoxTest.php b/tests/Test/BlackBoxTest.php
index d57f3a3..f3a2dc0 100644
--- a/tests/Test/BlackBoxTest.php
+++ b/tests/Test/BlackBoxTest.php
@@ -3,9 +3,9 @@
 
 use GuzzleHttp\Client;
 use GuzzleHttp\Promise;
-use PHPUnit_Framework_TestCase;
+use PHPUnit\Framework\TestCase;
 
-class BlackBoxTest extends PHPUnit_Framework_TestCase
+class BlackBoxTest extends TestCase
 {
     /**
      * @var Client
diff --git a/tests/Test/Prometheus/AbstractCollectorRegistryTest.php b/tests/Test/Prometheus/AbstractCollectorRegistryTest.php
index 237685c..e14f4e1 100644
--- a/tests/Test/Prometheus/AbstractCollectorRegistryTest.php
+++ b/tests/Test/Prometheus/AbstractCollectorRegistryTest.php
@@ -4,15 +4,16 @@
 namespace Test\Prometheus;
 
 
-use PHPUnit_Framework_TestCase;
+use PHPUnit\Framework\TestCase;
 use Prometheus\CollectorRegistry;
+use Prometheus\Exception\MetricNotFoundException;
 use Prometheus\Exception\MetricsRegistrationException;
 use Prometheus\Histogram;
 use Prometheus\RenderTextFormat;
 use Prometheus\Storage\Adapter;
 use Prometheus\Storage\Redis;
 
-abstract class AbstractCollectorRegistryTest extends PHPUnit_Framework_TestCase
+abstract class AbstractCollectorRegistryTest extends TestCase
 {
     /**
      * @var Adapter
@@ -195,7 +196,7 @@ public function itShouldIncreaseACounterWithoutNamespace()
 
     /**
      * @test
-     * @expectedException \Prometheus\Exception\MetricsRegistrationException
+     * @expectedException MetricsRegistrationException
      */
     public function itShouldForbidRegisteringTheSameCounterTwice()
     {
@@ -206,7 +207,7 @@ public function itShouldForbidRegisteringTheSameCounterTwice()
 
     /**
      * @test
-     * @expectedException \Prometheus\Exception\MetricsRegistrationException
+     * @expectedException MetricsRegistrationException
      */
     public function itShouldForbidRegisteringTheSameCounterWithDifferentLabels()
     {
@@ -217,7 +218,7 @@ public function itShouldForbidRegisteringTheSameCounterWithDifferentLabels()
 
     /**
      * @test
-     * @expectedException \Prometheus\Exception\MetricsRegistrationException
+     * @expectedException MetricsRegistrationException
      */
     public function itShouldForbidRegisteringTheSameHistogramTwice()
     {
@@ -228,7 +229,7 @@ public function itShouldForbidRegisteringTheSameHistogramTwice()
 
     /**
      * @test
-     * @expectedException \Prometheus\Exception\MetricsRegistrationException
+     * @expectedException MetricsRegistrationException
      */
     public function itShouldForbidRegisteringTheSameHistogramWithDifferentLabels()
     {
@@ -239,7 +240,7 @@ public function itShouldForbidRegisteringTheSameHistogramWithDifferentLabels()
 
     /**
      * @test
-     * @expectedException \Prometheus\Exception\MetricsRegistrationException
+     * @expectedException MetricsRegistrationException
      */
     public function itShouldForbidRegisteringTheSameGaugeTwice()
     {
@@ -250,7 +251,7 @@ public function itShouldForbidRegisteringTheSameGaugeTwice()
 
     /**
      * @test
-     * @expectedException \Prometheus\Exception\MetricsRegistrationException
+     * @expectedException MetricsRegistrationException
      */
     public function itShouldForbidRegisteringTheSameGaugeWithDifferentLabels()
     {
@@ -261,7 +262,7 @@ public function itShouldForbidRegisteringTheSameGaugeWithDifferentLabels()
 
     /**
      * @test
-     * @expectedException \Prometheus\Exception\MetricNotFoundException
+     * @expectedException MetricNotFoundException
      */
     public function itShouldThrowAnExceptionWhenGettingANonExistentMetric()
     {
diff --git a/tests/Test/Prometheus/AbstractCounterTest.php b/tests/Test/Prometheus/AbstractCounterTest.php
index 188310c..3487c0d 100644
--- a/tests/Test/Prometheus/AbstractCounterTest.php
+++ b/tests/Test/Prometheus/AbstractCounterTest.php
@@ -3,7 +3,8 @@
 
 namespace Test\Prometheus;
 
-use PHPUnit_Framework_TestCase;
+use InvalidArgumentException;
+use PHPUnit\Framework\TestCase;
 use Prometheus\Counter;
 use Prometheus\MetricFamilySamples;
 use Prometheus\Sample;
@@ -12,7 +13,7 @@
 /**
  * See https://prometheus.io/docs/instrumenting/exposition_formats/
  */
-abstract class AbstractCounterTest extends PHPUnit_Framework_TestCase
+abstract class AbstractCounterTest extends TestCase
 {
     /**
      * @var Adapter
@@ -125,7 +126,7 @@ public function itShouldIncreaseTheCounterByAnArbitraryInteger()
 
     /**
      * @test
-     * @expectedException \InvalidArgumentException
+     * @expectedException InvalidArgumentException
      */
     public function itShouldRejectInvalidMetricsNames()
     {
@@ -134,7 +135,7 @@ public function itShouldRejectInvalidMetricsNames()
 
     /**
      * @test
-     * @expectedException \InvalidArgumentException
+     * @expectedException InvalidArgumentException
      */
     public function itShouldRejectInvalidLabelNames()
     {
diff --git a/tests/Test/Prometheus/AbstractGaugeTest.php b/tests/Test/Prometheus/AbstractGaugeTest.php
index 33ad02c..32c2673 100644
--- a/tests/Test/Prometheus/AbstractGaugeTest.php
+++ b/tests/Test/Prometheus/AbstractGaugeTest.php
@@ -3,7 +3,8 @@
 
 namespace Test\Prometheus;
 
-use PHPUnit_Framework_TestCase;
+use InvalidArgumentException;
+use PHPUnit\Framework\TestCase;
 use Prometheus\Gauge;
 use Prometheus\MetricFamilySamples;
 use Prometheus\Sample;
@@ -12,7 +13,7 @@
 /**
  * See https://prometheus.io/docs/instrumenting/exposition_formats/
  */
-abstract class AbstractGaugeTest extends PHPUnit_Framework_TestCase
+abstract class AbstractGaugeTest extends TestCase
 {
     /**
      * @var Adapter
@@ -293,7 +294,7 @@ public function itShouldOverwriteWhenSettingTwice()
 
     /**
      * @test
-     * @expectedException \InvalidArgumentException
+     * @expectedException InvalidArgumentException
      */
     public function itShouldRejectInvalidMetricsNames()
     {
@@ -302,7 +303,7 @@ public function itShouldRejectInvalidMetricsNames()
 
     /**
      * @test
-     * @expectedException \InvalidArgumentException
+     * @expectedException InvalidArgumentException
      */
     public function itShouldRejectInvalidLabelNames()
     {
diff --git a/tests/Test/Prometheus/AbstractHistogramTest.php b/tests/Test/Prometheus/AbstractHistogramTest.php
index 358fcad..af982d5 100644
--- a/tests/Test/Prometheus/AbstractHistogramTest.php
+++ b/tests/Test/Prometheus/AbstractHistogramTest.php
@@ -3,7 +3,8 @@
 
 namespace Test\Prometheus;
 
-use PHPUnit_Framework_TestCase;
+use InvalidArgumentException;
+use PHPUnit\Framework\TestCase;
 use Prometheus\Histogram;
 use Prometheus\MetricFamilySamples;
 use Prometheus\Sample;
@@ -13,7 +14,7 @@
 /**
  * See https://prometheus.io/docs/instrumenting/exposition_formats/
  */
-abstract class AbstractHistogramTest extends PHPUnit_Framework_TestCase
+abstract class AbstractHistogramTest extends TestCase
 {
     /**
      * @var Adapter
@@ -374,7 +375,7 @@ public function itShouldProvideDefaultBuckets()
 
     /**
      * @test
-     * @expectedException \InvalidArgumentException
+     * @expectedException InvalidArgumentException
      * @expectedExceptionMessage Histogram buckets must be in increasing order
      */
     public function itShouldThrowAnExceptionWhenTheBucketSizesAreNotIncreasing()
@@ -384,7 +385,7 @@ public function itShouldThrowAnExceptionWhenTheBucketSizesAreNotIncreasing()
 
     /**
      * @test
-     * @expectedException \InvalidArgumentException
+     * @expectedException InvalidArgumentException
      * @expectedExceptionMessage Histogram must have at least one bucket
      */
     public function itShouldThrowAnExceptionWhenThereIsLessThanOneBucket()
@@ -394,7 +395,7 @@ public function itShouldThrowAnExceptionWhenThereIsLessThanOneBucket()
 
     /**
      * @test
-     * @expectedException \InvalidArgumentException
+     * @expectedException InvalidArgumentException
      * @expectedExceptionMessage Histogram cannot have a label named
      */
     public function itShouldThrowAnExceptionWhenThereIsALabelNamedLe()
@@ -404,7 +405,7 @@ public function itShouldThrowAnExceptionWhenThereIsALabelNamedLe()
 
     /**
      * @test
-     * @expectedException \InvalidArgumentException
+     * @expectedException InvalidArgumentException
      * @expectedExceptionMessage Invalid metric name
      */
     public function itShouldRejectInvalidMetricsNames()
@@ -414,7 +415,7 @@ public function itShouldRejectInvalidMetricsNames()
 
     /**
      * @test
-     * @expectedException \InvalidArgumentException
+     * @expectedException InvalidArgumentException
      * @expectedExceptionMessage Invalid label name
      */
     public function itShouldRejectInvalidLabelNames()
diff --git a/tests/Test/Prometheus/Storage/RedisTest.php b/tests/Test/Prometheus/Storage/RedisTest.php
index 8175475..dcaddba 100644
--- a/tests/Test/Prometheus/Storage/RedisTest.php
+++ b/tests/Test/Prometheus/Storage/RedisTest.php
@@ -1,21 +1,23 @@
 <?php
 
-
 namespace Prometheus\Storage;
 
+use PHPUnit\Framework\TestCase;
+use Prometheus\Exception\StorageException;
+
 /**
  * @requires extension redis
  */
-class RedisTest extends \PHPUnit_Framework_TestCase
+class RedisTest extends TestCase
 {
     /**
      * @test
-     * @expectedException \Prometheus\Exception\StorageException
+     * @expectedException StorageException
      * @expectedExceptionMessage Can't connect to Redis server
      */
     public function itShouldThrowAnExceptionOnConnectionFailure()
     {
-        $redis = new Redis(array('host' => 'doesntexist.test'));
+        $redis = new Redis(['host' => 'completely.fake.example.test']);
         $redis->flushRedis();
     }
 

From b2614eec085382a58e5951d0d931e199f69228f9 Mon Sep 17 00:00:00 2001
From: Daniel Noel-Davies <daniel.noel-davies@endclothing.com>
Date: Fri, 19 Jul 2019 11:45:10 +0100
Subject: [PATCH 02/28] Add json extension requirement

---
 composer.json | 1 +
 1 file changed, 1 insertion(+)

diff --git a/composer.json b/composer.json
index ef6c2cf..9feb833 100644
--- a/composer.json
+++ b/composer.json
@@ -12,6 +12,7 @@
     ],
     "require": {
         "php": ">=5.6.3",
+        "ext-json": "*",
         "guzzlehttp/guzzle": "^6.2",
         "symfony/polyfill-apcu": "^1.6"
     },

From 1a0cc231f33e784096ca5d75927d1b80f7a1d11b Mon Sep 17 00:00:00 2001
From: Daniel Noel-Davies <daniel.noel-davies@endclothing.com>
Date: Fri, 19 Jul 2019 11:45:44 +0100
Subject: [PATCH 03/28] Add docblocks

---
 src/Prometheus/Collector.php                  | 29 ++++++++++-
 src/Prometheus/CollectorRegistry.php          | 18 +++++--
 src/Prometheus/Counter.php                    |  2 -
 .../Exception/MetricNotFoundException.php     |  3 --
 .../MetricsRegistrationException.php          |  3 --
 src/Prometheus/Exception/StorageException.php |  3 --
 src/Prometheus/Gauge.php                      | 16 +++++-
 src/Prometheus/Histogram.php                  |  4 +-
 src/Prometheus/MetricFamilySamples.php        | 19 +++++++
 src/Prometheus/PushGateway.php                | 16 +++---
 src/Prometheus/RenderTextFormat.php           | 10 +++-
 src/Prometheus/Sample.php                     | 20 +++++++-
 src/Prometheus/Storage/APC.php                | 12 +++++
 src/Prometheus/Storage/InMemory.php           | 23 +++++++--
 src/Prometheus/Storage/Redis.php              | 49 ++++++++++++++++++-
 15 files changed, 195 insertions(+), 32 deletions(-)

diff --git a/src/Prometheus/Collector.php b/src/Prometheus/Collector.php
index 2b77554..bc85277 100644
--- a/src/Prometheus/Collector.php
+++ b/src/Prometheus/Collector.php
@@ -1,8 +1,6 @@
 <?php
-
 namespace Prometheus;
 
-
 use InvalidArgumentException;
 use Prometheus\Storage\Adapter;
 
@@ -10,9 +8,24 @@ abstract class Collector
 {
     const RE_METRIC_LABEL_NAME = '/^[a-zA-Z_:][a-zA-Z0-9_:]*$/';
 
+    /**
+     * @var Adapter
+     */
     protected $storageAdapter;
+
+    /**
+     * @var string
+     */
     protected $name;
+
+    /**
+     * @var string
+     */
     protected $help;
+
+    /**
+     * @var array
+     */
     protected $labels;
 
     /**
@@ -44,21 +57,33 @@ public function __construct(Adapter $storageAdapter, $namespace, $name, $help, $
      */
     public abstract function getType();
 
+    /**
+     * @return string
+     */
     public function getName()
     {
         return $this->name;
     }
 
+    /**
+     * @return array
+     */
     public function getLabelNames()
     {
         return $this->labels;
     }
 
+    /**
+     * @return string
+     */
     public function getHelp()
     {
         return $this->help;
     }
 
+    /**
+     * @return string
+     */
     public function getKey()
     {
         return sha1($this->getName() . serialize($this->getLabelNames()));
diff --git a/src/Prometheus/CollectorRegistry.php b/src/Prometheus/CollectorRegistry.php
index 9ff18e3..28a707a 100644
--- a/src/Prometheus/CollectorRegistry.php
+++ b/src/Prometheus/CollectorRegistry.php
@@ -1,9 +1,6 @@
 <?php
-
-
 namespace Prometheus;
 
-
 use Prometheus\Exception\MetricNotFoundException;
 use Prometheus\Exception\MetricsRegistrationException;
 use Prometheus\Storage\Adapter;
@@ -20,19 +17,26 @@ class CollectorRegistry
      * @var Adapter
      */
     private $storageAdapter;
+
     /**
      * @var Gauge[]
      */
     private $gauges = array();
+
     /**
      * @var Counter[]
      */
     private $counters = array();
+
     /**
      * @var Histogram[]
      */
     private $histograms = array();
 
+    /**
+     * CollectorRegistry constructor.
+     * @param Adapter $redisAdapter
+     */
     public function __construct(Adapter $redisAdapter)
     {
         $this->storageAdapter = $redisAdapter;
@@ -102,6 +106,7 @@ public function getGauge($namespace, $name)
      * @param string $help e.g. The duration something took in seconds.
      * @param array $labels e.g. ['controller', 'action']
      * @return Gauge
+     * @throws MetricsRegistrationException
      */
     public function getOrRegisterGauge($namespace, $name, $help, $labels = array())
     {
@@ -158,6 +163,7 @@ public function getCounter($namespace, $name)
      * @param string $help e.g. The number of requests made.
      * @param array $labels e.g. ['controller', 'action']
      * @return Counter
+     * @throws MetricsRegistrationException
      */
     public function getOrRegisterCounter($namespace, $name, $help, $labels = array())
     {
@@ -217,6 +223,7 @@ public function getHistogram($namespace, $name)
      * @param array $labels e.g. ['controller', 'action']
      * @param array $buckets e.g. [100, 200, 300]
      * @return Histogram
+     * @throws MetricsRegistrationException
      */
     public function getOrRegisterHistogram($namespace, $name, $help, $labels = array(), $buckets = null)
     {
@@ -228,6 +235,11 @@ public function getOrRegisterHistogram($namespace, $name, $help, $labels = array
         return $histogram;
     }
 
+    /**
+     * @param $namespace
+     * @param $name
+     * @return string
+     */
     private static function metricIdentifier($namespace, $name)
     {
         return $namespace . ":" . $name;
diff --git a/src/Prometheus/Counter.php b/src/Prometheus/Counter.php
index 3624c9c..e580ff6 100644
--- a/src/Prometheus/Counter.php
+++ b/src/Prometheus/Counter.php
@@ -1,8 +1,6 @@
 <?php
-
 namespace Prometheus;
 
-
 use Prometheus\Storage\Adapter;
 
 class Counter extends Collector
diff --git a/src/Prometheus/Exception/MetricNotFoundException.php b/src/Prometheus/Exception/MetricNotFoundException.php
index d35533f..f754777 100644
--- a/src/Prometheus/Exception/MetricNotFoundException.php
+++ b/src/Prometheus/Exception/MetricNotFoundException.php
@@ -1,9 +1,6 @@
 <?php
-
-
 namespace Prometheus\Exception;
 
-
 use Exception;
 
 /**
diff --git a/src/Prometheus/Exception/MetricsRegistrationException.php b/src/Prometheus/Exception/MetricsRegistrationException.php
index 673ad0b..5644811 100644
--- a/src/Prometheus/Exception/MetricsRegistrationException.php
+++ b/src/Prometheus/Exception/MetricsRegistrationException.php
@@ -1,9 +1,6 @@
 <?php
-
-
 namespace Prometheus\Exception;
 
-
 use Exception;
 
 /**
diff --git a/src/Prometheus/Exception/StorageException.php b/src/Prometheus/Exception/StorageException.php
index 641a739..e5e0f49 100644
--- a/src/Prometheus/Exception/StorageException.php
+++ b/src/Prometheus/Exception/StorageException.php
@@ -1,9 +1,6 @@
 <?php
-
-
 namespace Prometheus\Exception;
 
-
 use Exception;
 
 /**
diff --git a/src/Prometheus/Gauge.php b/src/Prometheus/Gauge.php
index 235e9ae..4c57f2c 100644
--- a/src/Prometheus/Gauge.php
+++ b/src/Prometheus/Gauge.php
@@ -1,9 +1,7 @@
 <?php
 
-
 namespace Prometheus;
 
-
 use Prometheus\Storage\Adapter;
 
 class Gauge extends Collector
@@ -39,11 +37,18 @@ public function getType()
         return self::TYPE;
     }
 
+    /**
+     * @param array $labels
+     */
     public function inc($labels = array())
     {
         $this->incBy(1, $labels);
     }
 
+    /**
+     * @param $value
+     * @param array $labels
+     */
     public function incBy($value, $labels = array())
     {
         $this->assertLabelsAreDefinedCorrectly($labels);
@@ -61,11 +66,18 @@ public function incBy($value, $labels = array())
         );
     }
 
+    /**
+     * @param array $labels
+     */
     public function dec($labels = array())
     {
         $this->decBy(1, $labels);
     }
 
+    /**
+     * @param $value
+     * @param array $labels
+     */
     public function decBy($value, $labels = array())
     {
         $this->incBy(-$value, $labels);
diff --git a/src/Prometheus/Histogram.php b/src/Prometheus/Histogram.php
index cafbcbe..a8e9107 100644
--- a/src/Prometheus/Histogram.php
+++ b/src/Prometheus/Histogram.php
@@ -2,7 +2,6 @@
 
 namespace Prometheus;
 
-
 use InvalidArgumentException;
 use Prometheus\Storage\Adapter;
 
@@ -10,6 +9,9 @@ class Histogram extends Collector
 {
     const TYPE = 'histogram';
 
+    /**
+     * @var array|null
+     */
     private $buckets;
 
     /**
diff --git a/src/Prometheus/MetricFamilySamples.php b/src/Prometheus/MetricFamilySamples.php
index e88e9aa..a3c79c1 100644
--- a/src/Prometheus/MetricFamilySamples.php
+++ b/src/Prometheus/MetricFamilySamples.php
@@ -4,10 +4,29 @@
 
 class MetricFamilySamples
 {
+    /**
+     * @var mixed
+     */
     private $name;
+
+    /**
+     * @var string
+     */
     private $type;
+
+    /**
+     * @var string
+     */
     private $help;
+
+    /**
+     * @var array
+     */
     private $labelNames;
+
+    /**
+     * @var array
+     */
     private $samples = array();
 
     /**
diff --git a/src/Prometheus/PushGateway.php b/src/Prometheus/PushGateway.php
index 42f3197..6cfc421 100644
--- a/src/Prometheus/PushGateway.php
+++ b/src/Prometheus/PushGateway.php
@@ -1,14 +1,15 @@
 <?php
 
-
 namespace Prometheus;
 
-
 use GuzzleHttp\Client;
 use RuntimeException;
 
 class PushGateway
 {
+    /**
+     * @var string
+     */
     private $address;
 
     /**
@@ -26,6 +27,7 @@ public function __construct($address)
      * @param CollectorRegistry $collectorRegistry
      * @param $job
      * @param $groupingKey
+     * @throws \GuzzleHttp\Exception\GuzzleException
      */
     public function push(CollectorRegistry $collectorRegistry, $job, $groupingKey = null)
     {
@@ -38,6 +40,7 @@ public function push(CollectorRegistry $collectorRegistry, $job, $groupingKey =
      * @param CollectorRegistry $collectorRegistry
      * @param $job
      * @param $groupingKey
+     * @throws \GuzzleHttp\Exception\GuzzleException
      */
     public function pushAdd(CollectorRegistry $collectorRegistry, $job, $groupingKey = null)
     {
@@ -49,6 +52,7 @@ public function pushAdd(CollectorRegistry $collectorRegistry, $job, $groupingKey
      * Uses HTTP POST.
      * @param $job
      * @param $groupingKey
+     * @throws \GuzzleHttp\Exception\GuzzleException
      */
     public function delete($job, $groupingKey = null)
     {
@@ -57,9 +61,10 @@ public function delete($job, $groupingKey = null)
 
     /**
      * @param CollectorRegistry $collectorRegistry
-     * @param $job
-     * @param $groupingKey
-     * @param $method
+     * @param string $job
+     * @param string $groupingKey
+     * @param string $method
+     * @throws \GuzzleHttp\Exception\GuzzleException
      */
     private function doRequest(CollectorRegistry $collectorRegistry, $job, $groupingKey, $method)
     {
@@ -88,5 +93,4 @@ private function doRequest(CollectorRegistry $collectorRegistry, $job, $grouping
             throw new RuntimeException($msg);
         }
     }
-
 }
diff --git a/src/Prometheus/RenderTextFormat.php b/src/Prometheus/RenderTextFormat.php
index 95fe2b5..1af77d6 100644
--- a/src/Prometheus/RenderTextFormat.php
+++ b/src/Prometheus/RenderTextFormat.php
@@ -2,7 +2,6 @@
 
 namespace Prometheus;
 
-
 class RenderTextFormat
 {
     const MIME_TYPE = 'text/plain; version=0.0.4';
@@ -30,6 +29,11 @@ public function render(array $metrics)
         return implode("\n", $lines) . "\n";
     }
 
+    /**
+     * @param MetricFamilySamples $metric
+     * @param Sample $sample
+     * @return string
+     */
     private function renderSample(MetricFamilySamples $metric, Sample $sample)
     {
         $escapedLabels = array();
@@ -45,6 +49,10 @@ private function renderSample(MetricFamilySamples $metric, Sample $sample)
         return $sample->getName() . ' ' . $sample->getValue();
     }
 
+    /**
+     * @param $v
+     * @return mixed
+     */
     private function escapeLabelValue($v)
     {
         $v = str_replace("\\", "\\\\", $v);
diff --git a/src/Prometheus/Sample.php b/src/Prometheus/Sample.php
index 9d9d1b3..a88a027 100644
--- a/src/Prometheus/Sample.php
+++ b/src/Prometheus/Sample.php
@@ -2,14 +2,32 @@
 
 namespace Prometheus;
 
-
 class Sample
 {
+    /**
+     * @var string
+     */
     private $name;
+
+    /**
+     * @var array
+     */
     private $labelNames;
+
+    /**
+     * @var array
+     */
     private $labelValues;
+
+    /**
+     * @var int|double
+     */
     private $value;
 
+    /**
+     * Sample constructor.
+     * @param array $data
+     */
     public function __construct(array $data)
     {
         $this->name = $data['name'];
diff --git a/src/Prometheus/Storage/APC.php b/src/Prometheus/Storage/APC.php
index 3d386fa..4c03b9b 100644
--- a/src/Prometheus/Storage/APC.php
+++ b/src/Prometheus/Storage/APC.php
@@ -23,6 +23,9 @@ public function collect()
         return $metrics;
     }
 
+    /**
+     * @param array $data
+     */
     public function updateHistogram(array $data)
     {
         // Initialize the sum
@@ -56,6 +59,9 @@ public function updateHistogram(array $data)
         apcu_inc($this->histogramBucketValueKey($data, $bucketToIncrease));
     }
 
+    /**
+     * @param array $data
+     */
     public function updateGauge(array $data)
     {
         $valueKey = $this->valueKey($data);
@@ -76,6 +82,9 @@ public function updateGauge(array $data)
         }
     }
 
+    /**
+     * @param array $data
+     */
     public function updateCounter(array $data)
     {
         $new = apcu_add($this->valueKey($data), 0);
@@ -298,6 +307,9 @@ private function fromInteger($val)
         return unpack('d', pack('Q', $val))[1];
     }
 
+    /**
+     * @param array $samples
+     */
     private function sortSamples(array &$samples)
     {
         usort($samples, function($a, $b){
diff --git a/src/Prometheus/Storage/InMemory.php b/src/Prometheus/Storage/InMemory.php
index 313dbf4..1c56de7 100644
--- a/src/Prometheus/Storage/InMemory.php
+++ b/src/Prometheus/Storage/InMemory.php
@@ -31,6 +31,9 @@ public function flushMemory()
         $this->histograms = [];
     }
 
+    /**
+     * @return array
+     */
     private function collectHistograms()
     {
         $histograms = [];
@@ -104,6 +107,10 @@ private function collectHistograms()
         return $histograms;
     }
 
+    /**
+     * @param array $metrics
+     * @return array
+     */
     private function internalCollect(array $metrics)
     {
         $result = [];
@@ -131,6 +138,9 @@ private function internalCollect(array $metrics)
         return $result;
     }
 
+    /**
+     * @param array $data
+     */
     public function updateHistogram(array $data)
     {
         // Initialize the sum
@@ -164,6 +174,9 @@ public function updateHistogram(array $data)
         $this->histograms[$metaKey]['samples'][$bucketKey] += 1;
     }
 
+    /**
+     * @param array $data
+     */
     public function updateGauge(array $data)
     {
         $metaKey = $this->metaKey($data);
@@ -184,6 +197,9 @@ public function updateGauge(array $data)
         }
     }
 
+    /**
+     * @param array $data
+     */
     public function updateCounter(array $data)
     {
         $metaKey = $this->metaKey($data);
@@ -206,9 +222,7 @@ public function updateCounter(array $data)
 
     /**
      * @param array $data
-     *
-     * @param       $bucket
-     *
+     * @param string $bucket
      * @return string
      */
     private function histogramBucketValueKey(array $data, $bucket)
@@ -256,6 +270,9 @@ private function metaData(array $data)
         return $metricsMetaData;
     }
 
+    /**
+     * @param array $samples
+     */
     private function sortSamples(array &$samples)
     {
         usort($samples, function ($a, $b) {
diff --git a/src/Prometheus/Storage/Redis.php b/src/Prometheus/Storage/Redis.php
index a099cd1..5babba0 100644
--- a/src/Prometheus/Storage/Redis.php
+++ b/src/Prometheus/Storage/Redis.php
@@ -1,8 +1,6 @@
 <?php
-
 namespace Prometheus\Storage;
 
-
 use InvalidArgumentException;
 use Prometheus\Counter;
 use Prometheus\Exception\StorageException;
@@ -15,12 +13,30 @@ class Redis implements Adapter
 {
     const PROMETHEUS_METRIC_KEYS_SUFFIX = '_METRIC_KEYS';
 
+    /**
+     * @var array
+     */
     private static $defaultOptions = array();
+
+    /**
+     * @var string
+     */
     private static $prefix = 'PROMETHEUS_';
 
+    /**
+     * @var array
+     */
     private $options;
+
+    /**
+     * @var \Redis
+     */
     private $redis;
 
+    /**
+     * Redis constructor.
+     * @param array $options
+     */
     public function __construct(array $options = array())
     {
         // with php 5.3 we cannot initialize the options directly on the field definition
@@ -56,6 +72,9 @@ public static function setDefaultOptions(array $options)
         self::$defaultOptions = array_merge(self::$defaultOptions, $options);
     }
 
+    /**
+     * @param $prefix
+     */
     public static function setPrefix($prefix)
     {
         self::$prefix = $prefix;
@@ -113,6 +132,10 @@ private function openConnection()
         }
     }
 
+    /**
+     * @param array $data
+     * @throws StorageException
+     */
     public function updateHistogram(array $data)
     {
         $this->openConnection();
@@ -147,6 +170,10 @@ public function updateHistogram(array $data)
         );
     }
 
+    /**
+     * @param array $data
+     * @throws StorageException
+     */
     public function updateGauge(array $data)
     {
         $this->openConnection();
@@ -182,6 +209,11 @@ public function updateGauge(array $data)
         );
     }
 
+    /**
+     * @param array $data
+     * @return mixed
+     * @throws StorageException
+     */
     public function updateCounter(array $data)
     {
         $this->openConnection();
@@ -211,6 +243,9 @@ public function updateCounter(array $data)
         return $result;
     }
 
+    /**
+     * @return array
+     */
     private function collectHistograms()
     {
         $keys = $this->redis->sMembers(self::$prefix . Histogram::TYPE . self::PROMETHEUS_METRIC_KEYS_SUFFIX);
@@ -285,6 +320,9 @@ private function collectHistograms()
         return $histograms;
     }
 
+    /**
+     * @return array
+     */
     private function collectGauges()
     {
         $keys = $this->redis->sMembers(self::$prefix . Gauge::TYPE . self::PROMETHEUS_METRIC_KEYS_SUFFIX);
@@ -311,6 +349,9 @@ private function collectGauges()
         return $gauges;
     }
 
+    /**
+     * @return array
+     */
     private function collectCounters()
     {
         $keys = $this->redis->sMembers(self::$prefix . Counter::TYPE . self::PROMETHEUS_METRIC_KEYS_SUFFIX);
@@ -337,6 +378,10 @@ private function collectCounters()
         return $counters;
     }
 
+    /**
+     * @param string $cmd
+     * @return string
+     */
     private function getRedisCommand($cmd)
     {
         switch ($cmd) {

From f553bb1d68131d30442a265d93239768d89cd6a0 Mon Sep 17 00:00:00 2001
From: Daniel Noel-Davies <daniel.noel-davies@endclothing.com>
Date: Fri, 19 Jul 2019 11:53:52 +0100
Subject: [PATCH 04/28] Fix full length expected exceptions in test suite

---
 .../Prometheus/AbstractCollectorRegistryTest.php   | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/tests/Test/Prometheus/AbstractCollectorRegistryTest.php b/tests/Test/Prometheus/AbstractCollectorRegistryTest.php
index e14f4e1..766c993 100644
--- a/tests/Test/Prometheus/AbstractCollectorRegistryTest.php
+++ b/tests/Test/Prometheus/AbstractCollectorRegistryTest.php
@@ -196,7 +196,7 @@ public function itShouldIncreaseACounterWithoutNamespace()
 
     /**
      * @test
-     * @expectedException MetricsRegistrationException
+     * @expectedException \Prometheus\Exception\MetricsRegistrationException
      */
     public function itShouldForbidRegisteringTheSameCounterTwice()
     {
@@ -207,7 +207,7 @@ public function itShouldForbidRegisteringTheSameCounterTwice()
 
     /**
      * @test
-     * @expectedException MetricsRegistrationException
+     * @expectedException \Prometheus\Exception\MetricsRegistrationException
      */
     public function itShouldForbidRegisteringTheSameCounterWithDifferentLabels()
     {
@@ -218,7 +218,7 @@ public function itShouldForbidRegisteringTheSameCounterWithDifferentLabels()
 
     /**
      * @test
-     * @expectedException MetricsRegistrationException
+     * @expectedException \Prometheus\Exception\MetricsRegistrationException
      */
     public function itShouldForbidRegisteringTheSameHistogramTwice()
     {
@@ -229,7 +229,7 @@ public function itShouldForbidRegisteringTheSameHistogramTwice()
 
     /**
      * @test
-     * @expectedException MetricsRegistrationException
+     * @expectedException \Prometheus\Exception\MetricsRegistrationException
      */
     public function itShouldForbidRegisteringTheSameHistogramWithDifferentLabels()
     {
@@ -240,7 +240,7 @@ public function itShouldForbidRegisteringTheSameHistogramWithDifferentLabels()
 
     /**
      * @test
-     * @expectedException MetricsRegistrationException
+     * @expectedException \Prometheus\Exception\MetricsRegistrationException
      */
     public function itShouldForbidRegisteringTheSameGaugeTwice()
     {
@@ -251,7 +251,7 @@ public function itShouldForbidRegisteringTheSameGaugeTwice()
 
     /**
      * @test
-     * @expectedException MetricsRegistrationException
+     * @expectedException \Prometheus\Exception\MetricsRegistrationException
      */
     public function itShouldForbidRegisteringTheSameGaugeWithDifferentLabels()
     {
@@ -262,7 +262,7 @@ public function itShouldForbidRegisteringTheSameGaugeWithDifferentLabels()
 
     /**
      * @test
-     * @expectedException MetricNotFoundException
+     * @expectedException \Prometheus\Exception\MetricNotFoundException
      */
     public function itShouldThrowAnExceptionWhenGettingANonExistentMetric()
     {

From f282d4cd93df3342bb85390e6c105c6b9a3d91fa Mon Sep 17 00:00:00 2001
From: Daniel Noel-Davies <daniel.noel-davies@endclothing.com>
Date: Mon, 22 Jul 2019 10:23:22 +0100
Subject: [PATCH 05/28] Add typehints, return types and all-round php 7
 goodness

---
 composer.json                                 |   2 +-
 examples/flush_adapter.php                    |   2 +-
 examples/metrics.php                          |   2 +-
 examples/pushgateway.php                      |   4 +-
 examples/some_counter.php                     |   2 +-
 examples/some_gauge.php                       |   2 +-
 examples/some_histogram.php                   |   2 +-
 phpunit.xml                                   |  26 +-
 src/Prometheus/Collector.php                  |  14 +-
 src/Prometheus/CollectorRegistry.php          |  32 +-
 src/Prometheus/Counter.php                    |  14 +-
 .../Exception/MetricNotFoundException.php     |   1 +
 .../MetricsRegistrationException.php          |   1 +
 src/Prometheus/Exception/StorageException.php |   1 +
 src/Prometheus/Gauge.php                      |  25 +-
 src/Prometheus/Histogram.php                  |  19 +-
 src/Prometheus/MetricFamilySamples.php        |  15 +-
 src/Prometheus/PushGateway.php                |  41 +-
 src/Prometheus/RenderTextFormat.php           |  23 +-
 src/Prometheus/Sample.php                     |  13 +-
 src/Prometheus/Storage/APC.php                | 167 ++++----
 src/Prometheus/Storage/Adapter.php            |  22 +-
 src/Prometheus/Storage/InMemory.php           |  79 ++--
 src/Prometheus/Storage/Redis.php              | 189 +++++----
 tests/Test/BlackBoxPushGatewayTest.php        |   4 +-
 .../AbstractCollectorRegistryTest.php         |  84 ++--
 tests/Test/Prometheus/AbstractCounterTest.php | 100 ++---
 tests/Test/Prometheus/AbstractGaugeTest.php   | 240 +++++------
 .../Test/Prometheus/AbstractHistogramTest.php | 384 +++++++++---------
 .../Redis/CollectorRegistryTest.php           |   2 +-
 tests/Test/Prometheus/Redis/CounterTest.php   |   2 +-
 tests/Test/Prometheus/Redis/GaugeTest.php     |   2 +-
 tests/Test/Prometheus/Redis/HistogramTest.php |   2 +-
 tests/Test/Prometheus/Storage/RedisTest.php   |   5 +-
 34 files changed, 811 insertions(+), 712 deletions(-)

diff --git a/composer.json b/composer.json
index 9feb833..22eec8a 100644
--- a/composer.json
+++ b/composer.json
@@ -11,7 +11,7 @@
         }
     ],
     "require": {
-        "php": ">=5.6.3",
+        "php": "^7.1",
         "ext-json": "*",
         "guzzlehttp/guzzle": "^6.2",
         "symfony/polyfill-apcu": "^1.6"
diff --git a/examples/flush_adapter.php b/examples/flush_adapter.php
index 0c3862d..028fdc7 100644
--- a/examples/flush_adapter.php
+++ b/examples/flush_adapter.php
@@ -6,7 +6,7 @@
 if ($adapter === 'redis') {
     define('REDIS_HOST', isset($_SERVER['REDIS_HOST']) ? $_SERVER['REDIS_HOST'] : '127.0.0.1');
 
-    $redisAdapter = new Prometheus\Storage\Redis(array('host' => REDIS_HOST));
+    $redisAdapter = new Prometheus\Storage\Redis(['host' => REDIS_HOST]);
     $redisAdapter->flushRedis();
 } elseif ($adapter === 'apc') {
     $apcAdapter = new Prometheus\Storage\APC();
diff --git a/examples/metrics.php b/examples/metrics.php
index fa89247..74a111b 100644
--- a/examples/metrics.php
+++ b/examples/metrics.php
@@ -9,7 +9,7 @@
 $adapter = $_GET['adapter'];
 
 if ($adapter === 'redis') {
-    Redis::setDefaultOptions(array('host' => isset($_SERVER['REDIS_HOST']) ? $_SERVER['REDIS_HOST'] : '127.0.0.1'));
+    Redis::setDefaultOptions(['host' => isset($_SERVER['REDIS_HOST']) ? $_SERVER['REDIS_HOST'] : '127.0.0.1']);
     $adapter = new Prometheus\Storage\Redis();
 } elseif ($adapter === 'apc') {
     $adapter = new Prometheus\Storage\APC();
diff --git a/examples/pushgateway.php b/examples/pushgateway.php
index feb2172..e78706f 100644
--- a/examples/pushgateway.php
+++ b/examples/pushgateway.php
@@ -8,7 +8,7 @@
 $adapter = $_GET['adapter'];
 
 if ($adapter === 'redis') {
-    Redis::setDefaultOptions(array('host' => isset($_SERVER['REDIS_HOST']) ? $_SERVER['REDIS_HOST'] : '127.0.0.1'));
+    Redis::setDefaultOptions(['host' => isset($_SERVER['REDIS_HOST']) ? $_SERVER['REDIS_HOST'] : '127.0.0.1']);
     $adapter = new Prometheus\Storage\Redis();
 } elseif ($adapter === 'apc') {
     $adapter = new Prometheus\Storage\APC();
@@ -22,4 +22,4 @@
 $counter->incBy(6, ['blue']);
 
 $pushGateway = new PushGateway('192.168.59.100:9091');
-$pushGateway->push($registry, 'my_job', array('instance'=>'foo'));
+$pushGateway->push($registry, 'my_job', ['instance'=>'foo']);
diff --git a/examples/some_counter.php b/examples/some_counter.php
index 823bfac..71e7290 100644
--- a/examples/some_counter.php
+++ b/examples/some_counter.php
@@ -8,7 +8,7 @@
 $adapter = $_GET['adapter'];
 
 if ($adapter === 'redis') {
-    Redis::setDefaultOptions(array('host' => isset($_SERVER['REDIS_HOST']) ? $_SERVER['REDIS_HOST'] : '127.0.0.1'));
+    Redis::setDefaultOptions(['host' => isset($_SERVER['REDIS_HOST']) ? $_SERVER['REDIS_HOST'] : '127.0.0.1']);
     $adapter = new Prometheus\Storage\Redis();
 } elseif ($adapter === 'apc') {
     $adapter = new Prometheus\Storage\APC();
diff --git a/examples/some_gauge.php b/examples/some_gauge.php
index b3e2382..ca2180f 100644
--- a/examples/some_gauge.php
+++ b/examples/some_gauge.php
@@ -11,7 +11,7 @@
 $adapter = $_GET['adapter'];
 
 if ($adapter === 'redis') {
-    Redis::setDefaultOptions(array('host' => isset($_SERVER['REDIS_HOST']) ? $_SERVER['REDIS_HOST'] : '127.0.0.1'));
+    Redis::setDefaultOptions(['host' => isset($_SERVER['REDIS_HOST']) ? $_SERVER['REDIS_HOST'] : '127.0.0.1']);
     $adapter = new Prometheus\Storage\Redis();
 } elseif ($adapter === 'apc') {
     $adapter = new Prometheus\Storage\APC();
diff --git a/examples/some_histogram.php b/examples/some_histogram.php
index 6b34809..babbced 100644
--- a/examples/some_histogram.php
+++ b/examples/some_histogram.php
@@ -10,7 +10,7 @@
 $adapter = $_GET['adapter'];
 
 if ($adapter === 'redis') {
-    Redis::setDefaultOptions(array('host' => isset($_SERVER['REDIS_HOST']) ? $_SERVER['REDIS_HOST'] : '127.0.0.1'));
+    Redis::setDefaultOptions(['host' => isset($_SERVER['REDIS_HOST']) ? $_SERVER['REDIS_HOST'] : '127.0.0.1']);
     $adapter = new Prometheus\Storage\Redis();
 } elseif ($adapter === 'apc') {
     $adapter = new Prometheus\Storage\APC();
diff --git a/phpunit.xml b/phpunit.xml
index c09d661..ab027cb 100644
--- a/phpunit.xml
+++ b/phpunit.xml
@@ -1,7 +1,21 @@
-<phpunit colors="true" bootstrap="./tests/bootstrap.php">
-    <testsuites>
-        <testsuite name="Test Suite">
-            <directory>./tests/Test/Prometheus</directory>
-        </testsuite>
-    </testsuites>
+<?xml version="1.0" encoding="UTF-8"?>
+<phpunit backupGlobals="false"
+         backupStaticAttributes="false"
+         bootstrap="tests/bootstrap.php"
+         colors="true"
+         convertErrorsToExceptions="true"
+         convertNoticesToExceptions="true"
+         convertWarningsToExceptions="true"
+         processIsolation="false"
+         stopOnFailure="false">
+<testsuites>
+    <testsuite name="Unit">
+        <directory>./tests/Test/Prometheus</directory>
+    </testsuite>
+</testsuites>
+<filter>
+    <whitelist processUncoveredFilesFromWhitelist="true">
+        <directory suffix=".php">./src/Prometheus</directory>
+    </whitelist>
+</filter>
 </phpunit>
diff --git a/src/Prometheus/Collector.php b/src/Prometheus/Collector.php
index bc85277..26e8275 100644
--- a/src/Prometheus/Collector.php
+++ b/src/Prometheus/Collector.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 namespace Prometheus;
 
 use InvalidArgumentException;
@@ -35,7 +37,7 @@ abstract class Collector
      * @param string $help
      * @param array $labels
      */
-    public function __construct(Adapter $storageAdapter, $namespace, $name, $help, $labels = array())
+    public function __construct(Adapter $storageAdapter, $namespace, $name, $help, $labels = [])
     {
         $this->storageAdapter = $storageAdapter;
         $metricName = ($namespace ? $namespace . '_' : '') . $name;
@@ -60,7 +62,7 @@ public abstract function getType();
     /**
      * @return string
      */
-    public function getName()
+    public function getName(): string
     {
         return $this->name;
     }
@@ -68,7 +70,7 @@ public function getName()
     /**
      * @return array
      */
-    public function getLabelNames()
+    public function getLabelNames(): array
     {
         return $this->labels;
     }
@@ -76,7 +78,7 @@ public function getLabelNames()
     /**
      * @return string
      */
-    public function getHelp()
+    public function getHelp(): string
     {
         return $this->help;
     }
@@ -84,7 +86,7 @@ public function getHelp()
     /**
      * @return string
      */
-    public function getKey()
+    public function getKey(): string
     {
         return sha1($this->getName() . serialize($this->getLabelNames()));
     }
@@ -92,7 +94,7 @@ public function getKey()
     /**
      * @param $labels
      */
-    protected function assertLabelsAreDefinedCorrectly($labels)
+    protected function assertLabelsAreDefinedCorrectly($labels): void
     {
         if (count($labels) != count($this->labels)) {
             throw new InvalidArgumentException(sprintf('Labels are not defined correctly: ', print_r($labels, true)));
diff --git a/src/Prometheus/CollectorRegistry.php b/src/Prometheus/CollectorRegistry.php
index 28a707a..739e9c4 100644
--- a/src/Prometheus/CollectorRegistry.php
+++ b/src/Prometheus/CollectorRegistry.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 namespace Prometheus;
 
 use Prometheus\Exception\MetricNotFoundException;
@@ -21,17 +23,17 @@ class CollectorRegistry
     /**
      * @var Gauge[]
      */
-    private $gauges = array();
+    private $gauges = [];
 
     /**
      * @var Counter[]
      */
-    private $counters = array();
+    private $counters = [];
 
     /**
      * @var Histogram[]
      */
-    private $histograms = array();
+    private $histograms = [];
 
     /**
      * CollectorRegistry constructor.
@@ -45,7 +47,7 @@ public function __construct(Adapter $redisAdapter)
     /**
      * @return CollectorRegistry
      */
-    public static function getDefault()
+    public static function getDefault(): CollectorRegistry
     {
         if (!self::$defaultRegistry) {
             return self::$defaultRegistry = new static(new Redis());
@@ -56,7 +58,7 @@ public static function getDefault()
     /**
      * @return MetricFamilySamples[]
      */
-    public function getMetricFamilySamples()
+    public function getMetricFamilySamples(): array
     {
         return $this->storageAdapter->collect();
     }
@@ -69,7 +71,7 @@ public function getMetricFamilySamples()
      * @return Gauge
      * @throws MetricsRegistrationException
      */
-    public function registerGauge($namespace, $name, $help, $labels = array())
+    public function registerGauge($namespace, $name, $help, $labels = []): Gauge
     {
         $metricIdentifier = self::metricIdentifier($namespace, $name);
         if (isset($this->gauges[$metricIdentifier])) {
@@ -91,7 +93,7 @@ public function registerGauge($namespace, $name, $help, $labels = array())
      * @return Gauge
      * @throws MetricNotFoundException
      */
-    public function getGauge($namespace, $name)
+    public function getGauge($namespace, $name): Gauge
     {
         $metricIdentifier = self::metricIdentifier($namespace, $name);
         if (!isset($this->gauges[$metricIdentifier])) {
@@ -108,7 +110,7 @@ public function getGauge($namespace, $name)
      * @return Gauge
      * @throws MetricsRegistrationException
      */
-    public function getOrRegisterGauge($namespace, $name, $help, $labels = array())
+    public function getOrRegisterGauge($namespace, $name, $help, $labels = []): Gauge
     {
         try {
             $gauge = $this->getGauge($namespace, $name);
@@ -126,7 +128,7 @@ public function getOrRegisterGauge($namespace, $name, $help, $labels = array())
      * @return Counter
      * @throws MetricsRegistrationException
      */
-    public function registerCounter($namespace, $name, $help, $labels = array())
+    public function registerCounter($namespace, $name, $help, $labels = []): Counter
     {
         $metricIdentifier = self::metricIdentifier($namespace, $name);
         if (isset($this->counters[$metricIdentifier])) {
@@ -148,7 +150,7 @@ public function registerCounter($namespace, $name, $help, $labels = array())
      * @return Counter
      * @throws MetricNotFoundException
      */
-    public function getCounter($namespace, $name)
+    public function getCounter($namespace, $name): Counter
     {
         $metricIdentifier = self::metricIdentifier($namespace, $name);
         if (!isset($this->counters[$metricIdentifier])) {
@@ -165,7 +167,7 @@ public function getCounter($namespace, $name)
      * @return Counter
      * @throws MetricsRegistrationException
      */
-    public function getOrRegisterCounter($namespace, $name, $help, $labels = array())
+    public function getOrRegisterCounter($namespace, $name, $help, $labels = []): Counter
     {
         try {
             $counter = $this->getCounter($namespace, $name);
@@ -184,7 +186,7 @@ public function getOrRegisterCounter($namespace, $name, $help, $labels = array()
      * @return Histogram
      * @throws MetricsRegistrationException
      */
-    public function registerHistogram($namespace, $name, $help, $labels = array(), $buckets = null)
+    public function registerHistogram($namespace, $name, $help, $labels = [], $buckets = null): Histogram
     {
         $metricIdentifier = self::metricIdentifier($namespace, $name);
         if (isset($this->histograms[$metricIdentifier])) {
@@ -207,7 +209,7 @@ public function registerHistogram($namespace, $name, $help, $labels = array(), $
      * @return Histogram
      * @throws MetricNotFoundException
      */
-    public function getHistogram($namespace, $name)
+    public function getHistogram($namespace, $name): Histogram
     {
         $metricIdentifier = self::metricIdentifier($namespace, $name);
         if (!isset($this->histograms[$metricIdentifier])) {
@@ -225,7 +227,7 @@ public function getHistogram($namespace, $name)
      * @return Histogram
      * @throws MetricsRegistrationException
      */
-    public function getOrRegisterHistogram($namespace, $name, $help, $labels = array(), $buckets = null)
+    public function getOrRegisterHistogram($namespace, $name, $help, $labels = [], $buckets = null): Histogram
     {
         try {
             $histogram = $this->getHistogram($namespace, $name);
@@ -240,7 +242,7 @@ public function getOrRegisterHistogram($namespace, $name, $help, $labels = array
      * @param $name
      * @return string
      */
-    private static function metricIdentifier($namespace, $name)
+    private static function metricIdentifier($namespace, $name): string
     {
         return $namespace . ":" . $name;
     }
diff --git a/src/Prometheus/Counter.php b/src/Prometheus/Counter.php
index e580ff6..ae8e726 100644
--- a/src/Prometheus/Counter.php
+++ b/src/Prometheus/Counter.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types = 1);
+
 namespace Prometheus;
 
 use Prometheus\Storage\Adapter;
@@ -10,7 +12,7 @@ class Counter extends Collector
     /**
      * @return string
      */
-    public function getType()
+    public function getType(): string
     {
         return self::TYPE;
     }
@@ -18,7 +20,7 @@ public function getType()
     /**
      * @param array $labels e.g. ['status', 'opcode']
      */
-    public function inc(array $labels = array())
+    public function inc(array $labels = []): void
     {
         $this->incBy(1, $labels);
     }
@@ -27,20 +29,20 @@ public function inc(array $labels = array())
      * @param int $count e.g. 2
      * @param array $labels e.g. ['status', 'opcode']
      */
-    public function incBy($count, array $labels = array())
+    public function incBy($count, array $labels = []): void
     {
         $this->assertLabelsAreDefinedCorrectly($labels);
 
         $this->storageAdapter->updateCounter(
-            array(
+            [
                 'name' => $this->getName(),
                 'help' => $this->getHelp(),
                 'type' => $this->getType(),
                 'labelNames' => $this->getLabelNames(),
                 'labelValues' => $labels,
                 'value' => $count,
-                'command' => Adapter::COMMAND_INCREMENT_INTEGER
-            )
+                'command' => Adapter::COMMAND_INCREMENT_INTEGER,
+            ]
         );
     }
 }
diff --git a/src/Prometheus/Exception/MetricNotFoundException.php b/src/Prometheus/Exception/MetricNotFoundException.php
index f754777..bb3d51c 100644
--- a/src/Prometheus/Exception/MetricNotFoundException.php
+++ b/src/Prometheus/Exception/MetricNotFoundException.php
@@ -1,4 +1,5 @@
 <?php
+
 namespace Prometheus\Exception;
 
 use Exception;
diff --git a/src/Prometheus/Exception/MetricsRegistrationException.php b/src/Prometheus/Exception/MetricsRegistrationException.php
index 5644811..db127ea 100644
--- a/src/Prometheus/Exception/MetricsRegistrationException.php
+++ b/src/Prometheus/Exception/MetricsRegistrationException.php
@@ -1,4 +1,5 @@
 <?php
+
 namespace Prometheus\Exception;
 
 use Exception;
diff --git a/src/Prometheus/Exception/StorageException.php b/src/Prometheus/Exception/StorageException.php
index e5e0f49..5a1f038 100644
--- a/src/Prometheus/Exception/StorageException.php
+++ b/src/Prometheus/Exception/StorageException.php
@@ -1,4 +1,5 @@
 <?php
+
 namespace Prometheus\Exception;
 
 use Exception;
diff --git a/src/Prometheus/Gauge.php b/src/Prometheus/Gauge.php
index 4c57f2c..9339782 100644
--- a/src/Prometheus/Gauge.php
+++ b/src/Prometheus/Gauge.php
@@ -1,4 +1,5 @@
 <?php
+declare(strict_types = 1);
 
 namespace Prometheus;
 
@@ -12,27 +13,27 @@ class Gauge extends Collector
      * @param double $value e.g. 123
      * @param array $labels e.g. ['status', 'opcode']
      */
-    public function set($value, $labels = array())
+    public function set(float $value, array $labels = []): void
     {
         $this->assertLabelsAreDefinedCorrectly($labels);
 
         $this->storageAdapter->updateGauge(
-            array(
+            [
                 'name' => $this->getName(),
                 'help' => $this->getHelp(),
                 'type' => $this->getType(),
                 'labelNames' => $this->getLabelNames(),
                 'labelValues' => $labels,
                 'value' => $value,
-                'command' => Adapter::COMMAND_SET
-            )
+                'command' => Adapter::COMMAND_SET,
+            ]
         );
     }
 
     /**
      * @return string
      */
-    public function getType()
+    public function getType(): string
     {
         return self::TYPE;
     }
@@ -40,7 +41,7 @@ public function getType()
     /**
      * @param array $labels
      */
-    public function inc($labels = array())
+    public function inc($labels = []): void
     {
         $this->incBy(1, $labels);
     }
@@ -49,27 +50,27 @@ public function inc($labels = array())
      * @param $value
      * @param array $labels
      */
-    public function incBy($value, $labels = array())
+    public function incBy($value, array $labels = []): void
     {
         $this->assertLabelsAreDefinedCorrectly($labels);
 
         $this->storageAdapter->updateGauge(
-            array(
+            [
                 'name' => $this->getName(),
                 'help' => $this->getHelp(),
                 'type' => $this->getType(),
                 'labelNames' => $this->getLabelNames(),
                 'labelValues' => $labels,
                 'value' => $value,
-                'command' => Adapter::COMMAND_INCREMENT_FLOAT
-            )
+                'command' => Adapter::COMMAND_INCREMENT_FLOAT,
+            ]
         );
     }
 
     /**
      * @param array $labels
      */
-    public function dec($labels = array())
+    public function dec($labels = []): void
     {
         $this->decBy(1, $labels);
     }
@@ -78,7 +79,7 @@ public function dec($labels = array())
      * @param $value
      * @param array $labels
      */
-    public function decBy($value, $labels = array())
+    public function decBy($value, $labels = []): void
     {
         $this->incBy(-$value, $labels);
     }
diff --git a/src/Prometheus/Histogram.php b/src/Prometheus/Histogram.php
index a8e9107..f36cf0f 100644
--- a/src/Prometheus/Histogram.php
+++ b/src/Prometheus/Histogram.php
@@ -1,4 +1,5 @@
 <?php
+declare(strict_types = 1);
 
 namespace Prometheus;
 
@@ -22,7 +23,7 @@ class Histogram extends Collector
      * @param array $labels
      * @param array $buckets
      */
-    public function __construct(Adapter $adapter, $namespace, $name, $help, $labels = array(), $buckets = null)
+    public function __construct(Adapter $adapter, $namespace, $name, $help, $labels = [], $buckets = null)
     {
         parent::__construct($adapter, $namespace, $name, $help, $labels);
 
@@ -54,23 +55,23 @@ public function __construct(Adapter $adapter, $namespace, $name, $help, $labels
      * List of default buckets suitable for typical web application latency metrics
      * @return array
      */
-    public static function getDefaultBuckets()
+    public static function getDefaultBuckets(): array
     {
-        return array(
-            0.005, 0.01, 0.025, 0.05, 0.075, 0.1, 0.25, 0.5, 0.75, 1.0, 2.5, 5.0, 7.5, 10.0
-        );
+        return [
+            0.005, 0.01, 0.025, 0.05, 0.075, 0.1, 0.25, 0.5, 0.75, 1.0, 2.5, 5.0, 7.5, 10.0,
+        ];
     }
 
     /**
      * @param double $value e.g. 123
      * @param array $labels e.g. ['status', 'opcode']
      */
-    public function observe($value, $labels = array())
+    public function observe(float $value, array $labels = []): void
     {
         $this->assertLabelsAreDefinedCorrectly($labels);
 
         $this->storageAdapter->updateHistogram(
-            array(
+            [
                 'value' => $value,
                 'name' => $this->getName(),
                 'help' => $this->getHelp(),
@@ -78,14 +79,14 @@ public function observe($value, $labels = array())
                 'labelNames' => $this->getLabelNames(),
                 'labelValues' => $labels,
                 'buckets' => $this->buckets,
-            )
+            ]
         );
     }
 
     /**
      * @return string
      */
-    public function getType()
+    public function getType(): string
     {
         return self::TYPE;
     }
diff --git a/src/Prometheus/MetricFamilySamples.php b/src/Prometheus/MetricFamilySamples.php
index a3c79c1..f600540 100644
--- a/src/Prometheus/MetricFamilySamples.php
+++ b/src/Prometheus/MetricFamilySamples.php
@@ -1,4 +1,5 @@
 <?php
+declare(strict_types = 1);
 
 namespace Prometheus;
 
@@ -27,7 +28,7 @@ class MetricFamilySamples
     /**
      * @var array
      */
-    private $samples = array();
+    private $samples = [];
 
     /**
      * @param array $data
@@ -46,7 +47,7 @@ public function __construct(array $data)
     /**
      * @return string
      */
-    public function getName()
+    public function getName(): string
     {
         return $this->name;
     }
@@ -54,7 +55,7 @@ public function getName()
     /**
      * @return string
      */
-    public function getType()
+    public function getType(): string
     {
         return $this->type;
     }
@@ -62,7 +63,7 @@ public function getType()
     /**
      * @return string
      */
-    public function getHelp()
+    public function getHelp(): string
     {
         return $this->help;
     }
@@ -70,7 +71,7 @@ public function getHelp()
     /**
      * @return Sample[]
      */
-    public function getSamples()
+    public function getSamples(): array
     {
         return $this->samples;
     }
@@ -78,7 +79,7 @@ public function getSamples()
     /**
      * @return array
      */
-    public function getLabelNames()
+    public function getLabelNames(): array
     {
         return $this->labelNames;
     }
@@ -86,7 +87,7 @@ public function getLabelNames()
     /**
      * @return bool
      */
-    public function hasLabelNames()
+    public function hasLabelNames(): bool
     {
         return !empty($this->labelNames);
     }
diff --git a/src/Prometheus/PushGateway.php b/src/Prometheus/PushGateway.php
index 6cfc421..e8792af 100644
--- a/src/Prometheus/PushGateway.php
+++ b/src/Prometheus/PushGateway.php
@@ -1,8 +1,10 @@
 <?php
+declare(strict_types = 1);
 
 namespace Prometheus;
 
 use GuzzleHttp\Client;
+use GuzzleHttp\Exception\GuzzleException;
 use RuntimeException;
 
 class PushGateway
@@ -25,11 +27,11 @@ public function __construct($address)
      * Pushes all metrics in a Collector, replacing all those with the same job.
      * Uses HTTP PUT.
      * @param CollectorRegistry $collectorRegistry
-     * @param $job
-     * @param $groupingKey
-     * @throws \GuzzleHttp\Exception\GuzzleException
+     * @param string $job
+     * @param array $groupingKey
+     * @throws GuzzleException
      */
-    public function push(CollectorRegistry $collectorRegistry, $job, $groupingKey = null)
+    public function push(CollectorRegistry $collectorRegistry, string $job, array $groupingKey = null): void
     {
         $this->doRequest($collectorRegistry, $job, $groupingKey, 'put');
     }
@@ -40,9 +42,9 @@ public function push(CollectorRegistry $collectorRegistry, $job, $groupingKey =
      * @param CollectorRegistry $collectorRegistry
      * @param $job
      * @param $groupingKey
-     * @throws \GuzzleHttp\Exception\GuzzleException
+     * @throws GuzzleException
      */
-    public function pushAdd(CollectorRegistry $collectorRegistry, $job, $groupingKey = null)
+    public function pushAdd(CollectorRegistry $collectorRegistry, string $job, array $groupingKey = null): void
     {
         $this->doRequest($collectorRegistry, $job, $groupingKey, 'post');
     }
@@ -50,11 +52,11 @@ public function pushAdd(CollectorRegistry $collectorRegistry, $job, $groupingKey
     /**
      * Deletes metrics from the Push Gateway.
      * Uses HTTP POST.
-     * @param $job
-     * @param $groupingKey
-     * @throws \GuzzleHttp\Exception\GuzzleException
+     * @param string $job
+     * @param array $groupingKey
+     * @throws GuzzleException
      */
-    public function delete($job, $groupingKey = null)
+    public function delete(string $job, array $groupingKey = null): void
     {
         $this->doRequest(null, $job, $groupingKey, 'delete');
     }
@@ -62,11 +64,11 @@ public function delete($job, $groupingKey = null)
     /**
      * @param CollectorRegistry $collectorRegistry
      * @param string $job
-     * @param string $groupingKey
+     * @param array $groupingKey
      * @param string $method
-     * @throws \GuzzleHttp\Exception\GuzzleException
+     * @throws GuzzleException
      */
-    private function doRequest(CollectorRegistry $collectorRegistry, $job, $groupingKey, $method)
+    private function doRequest(CollectorRegistry $collectorRegistry, string $job, array $groupingKey, $method): void
     {
         $url = "http://" . $this->address . "/metrics/job/" . $job;
         if (!empty($groupingKey)) {
@@ -75,13 +77,13 @@ private function doRequest(CollectorRegistry $collectorRegistry, $job, $grouping
             }
         }
         $client = new Client();
-        $requestOptions = array(
-            'headers' => array(
-                'Content-Type' => RenderTextFormat::MIME_TYPE
-            ),
+        $requestOptions = [
+            'headers' => [
+                'Content-Type' => RenderTextFormat::MIME_TYPE,
+            ],
             'connect_timeout' => 10,
             'timeout' => 20,
-        );
+        ];
         if ($method != 'delete') {
             $renderer = new RenderTextFormat();
             $requestOptions['body'] = $renderer->render($collectorRegistry->getMetricFamilySamples());
@@ -89,7 +91,8 @@ private function doRequest(CollectorRegistry $collectorRegistry, $job, $grouping
         $response = $client->request($method, $url, $requestOptions);
         $statusCode = $response->getStatusCode();
         if ($statusCode != 202) {
-            $msg = "Unexpected status code " . $statusCode . " received from push gateway " . $this->address . ": " . $response->getBody();
+            $msg = "Unexpected status code " . $statusCode . " received from push gateway " . $this->address . ": " . $response->getBody(
+                );
             throw new RuntimeException($msg);
         }
     }
diff --git a/src/Prometheus/RenderTextFormat.php b/src/Prometheus/RenderTextFormat.php
index 1af77d6..c0b3e70 100644
--- a/src/Prometheus/RenderTextFormat.php
+++ b/src/Prometheus/RenderTextFormat.php
@@ -1,4 +1,5 @@
 <?php
+declare(strict_types = 1);
 
 namespace Prometheus;
 
@@ -10,14 +11,16 @@ class RenderTextFormat
      * @param MetricFamilySamples[] $metrics
      * @return string
      */
-    public function render(array $metrics)
+    public function render(array $metrics): string
     {
-        usort($metrics, function(MetricFamilySamples $a, MetricFamilySamples $b)
-        {
-            return strcmp($a->getName(), $b->getName());
-        });
+        usort(
+            $metrics,
+            function (MetricFamilySamples $a, MetricFamilySamples $b) {
+                return strcmp($a->getName(), $b->getName());
+            }
+        );
 
-        $lines = array();
+        $lines = [];
 
         foreach ($metrics as $metric) {
             $lines[] = "# HELP " . $metric->getName() . " {$metric->getHelp()}";
@@ -34,9 +37,9 @@ public function render(array $metrics)
      * @param Sample $sample
      * @return string
      */
-    private function renderSample(MetricFamilySamples $metric, Sample $sample)
+    private function renderSample(MetricFamilySamples $metric, Sample $sample): string
     {
-        $escapedLabels = array();
+        $escapedLabels = [];
 
         $labelNames = $metric->getLabelNames();
         if ($metric->hasLabelNames() || $sample->hasLabelNames()) {
@@ -51,9 +54,9 @@ private function renderSample(MetricFamilySamples $metric, Sample $sample)
 
     /**
      * @param $v
-     * @return mixed
+     * @return string
      */
-    private function escapeLabelValue($v)
+    private function escapeLabelValue($v): string
     {
         $v = str_replace("\\", "\\\\", $v);
         $v = str_replace("\n", "\\n", $v);
diff --git a/src/Prometheus/Sample.php b/src/Prometheus/Sample.php
index a88a027..3ed624b 100644
--- a/src/Prometheus/Sample.php
+++ b/src/Prometheus/Sample.php
@@ -1,4 +1,5 @@
 <?php
+declare(strict_types = 1);
 
 namespace Prometheus;
 
@@ -39,7 +40,7 @@ public function __construct(array $data)
     /**
      * @return string
      */
-    public function getName()
+    public function getName(): string
     {
         return $this->name;
     }
@@ -47,7 +48,7 @@ public function getName()
     /**
      * @return array
      */
-    public function getLabelNames()
+    public function getLabelNames(): array
     {
         return (array)$this->labelNames;
     }
@@ -55,7 +56,7 @@ public function getLabelNames()
     /**
      * @return array
      */
-    public function getLabelValues()
+    public function getLabelValues(): array
     {
         return (array)$this->labelValues;
     }
@@ -63,15 +64,15 @@ public function getLabelValues()
     /**
      * @return int|double
      */
-    public function getValue()
+    public function getValue(): string
     {
-        return $this->value;
+        return (string) $this->value;
     }
 
     /**
      * @return bool
      */
-    public function hasLabelNames()
+    public function hasLabelNames(): bool
     {
         return !empty($this->labelNames);
     }
diff --git a/src/Prometheus/Storage/APC.php b/src/Prometheus/Storage/APC.php
index 4c03b9b..e7a8864 100644
--- a/src/Prometheus/Storage/APC.php
+++ b/src/Prometheus/Storage/APC.php
@@ -1,9 +1,8 @@
 <?php
-
+declare(strict_types=1);
 
 namespace Prometheus\Storage;
 
-
 use APCUIterator;
 use Prometheus\MetricFamilySamples;
 use RuntimeException;
@@ -15,7 +14,7 @@ class APC implements Adapter
     /**
      * @return MetricFamilySamples[]
      */
-    public function collect()
+    public function collect(): array
     {
         $metrics = $this->collectHistograms();
         $metrics = array_merge($metrics, $this->collectGauges());
@@ -26,7 +25,7 @@ public function collect()
     /**
      * @param array $data
      */
-    public function updateHistogram(array $data)
+    public function updateHistogram(array $data): void
     {
         // Initialize the sum
         $sumKey = $this->histogramBucketValueKey($data, 'sum');
@@ -62,7 +61,7 @@ public function updateHistogram(array $data)
     /**
      * @param array $data
      */
-    public function updateGauge(array $data)
+    public function updateGauge(array $data): void
     {
         $valueKey = $this->valueKey($data);
         if ($data['command'] == Adapter::COMMAND_SET) {
@@ -85,7 +84,7 @@ public function updateGauge(array $data)
     /**
      * @param array $data
      */
-    public function updateCounter(array $data)
+    public function updateCounter(array $data): void
     {
         $new = apcu_add($this->valueKey($data), 0);
         if ($new) {
@@ -94,56 +93,65 @@ public function updateCounter(array $data)
         apcu_inc($this->valueKey($data), $data['value']);
     }
 
-    public function flushAPC()
+    /**
+     * @return void
+     */
+    public function flushAPC(): void
     {
-       apcu_clear_cache();
+        apcu_clear_cache();
     }
 
     /**
      * @param array $data
      * @return string
      */
-    private function metaKey(array $data)
+    private function metaKey(array $data): string
     {
-        return implode(':', array(self::PROMETHEUS_PREFIX, $data['type'], $data['name'], 'meta'));
+        return implode(':', [self::PROMETHEUS_PREFIX, $data['type'], $data['name'], 'meta']);
     }
 
     /**
      * @param array $data
      * @return string
      */
-    private function valueKey(array $data)
+    private function valueKey(array $data): string
     {
-        return implode(':', array(
-            self::PROMETHEUS_PREFIX,
-            $data['type'],
-            $data['name'],
-            $this->encodeLabelValues($data['labelValues']),
-            'value'
-        ));
+        return implode(
+            ':',
+            [
+                self::PROMETHEUS_PREFIX,
+                $data['type'],
+                $data['name'],
+                $this->encodeLabelValues($data['labelValues']),
+                'value',
+            ]
+        );
     }
 
     /**
      * @param array $data
      * @return string
      */
-    private function histogramBucketValueKey(array $data, $bucket)
+    private function histogramBucketValueKey(array $data, $bucket): string
     {
-        return implode(':', array(
-            self::PROMETHEUS_PREFIX,
-            $data['type'],
-            $data['name'],
-            $this->encodeLabelValues($data['labelValues']),
-            $bucket,
-            'value'
-        ));
+        return implode(
+            ':',
+            [
+                self::PROMETHEUS_PREFIX,
+                $data['type'],
+                $data['name'],
+                $this->encodeLabelValues($data['labelValues']),
+                $bucket,
+                'value',
+            ]
+        );
     }
 
     /**
      * @param array $data
      * @return array
      */
-    private function metaData(array $data)
+    private function metaData(array $data): array
     {
         $metricsMetaData = $data;
         unset($metricsMetaData['value']);
@@ -155,26 +163,26 @@ private function metaData(array $data)
     /**
      * @return array
      */
-    private function collectCounters()
+    private function collectCounters(): array
     {
-        $counters = array();
+        $counters = [];
         foreach (new APCUIterator('/^prom:counter:.*:meta/') as $counter) {
             $metaData = json_decode($counter['value'], true);
-            $data = array(
+            $data = [
                 'name' => $metaData['name'],
                 'help' => $metaData['help'],
                 'type' => $metaData['type'],
                 'labelNames' => $metaData['labelNames'],
-            );
+            ];
             foreach (new APCUIterator('/^prom:counter:' . $metaData['name'] . ':.*:value/') as $value) {
                 $parts = explode(':', $value['key']);
                 $labelValues = $parts[3];
-                $data['samples'][] = array(
+                $data['samples'][] = [
                     'name' => $metaData['name'],
-                    'labelNames' => array(),
+                    'labelNames' => [],
                     'labelValues' => $this->decodeLabelValues($labelValues),
-                    'value' => $value['value']
-                );
+                    'value' => $value['value'],
+                ];
             }
             $this->sortSamples($data['samples']);
             $counters[] = new MetricFamilySamples($data);
@@ -185,26 +193,26 @@ private function collectCounters()
     /**
      * @return array
      */
-    private function collectGauges()
+    private function collectGauges(): array
     {
-        $gauges = array();
+        $gauges = [];
         foreach (new APCUIterator('/^prom:gauge:.*:meta/') as $gauge) {
             $metaData = json_decode($gauge['value'], true);
-            $data = array(
+            $data = [
                 'name' => $metaData['name'],
                 'help' => $metaData['help'],
                 'type' => $metaData['type'],
                 'labelNames' => $metaData['labelNames'],
-            );
+            ];
             foreach (new APCUIterator('/^prom:gauge:' . $metaData['name'] . ':.*:value/') as $value) {
                 $parts = explode(':', $value['key']);
                 $labelValues = $parts[3];
-                $data['samples'][] = array(
+                $data['samples'][] = [
                     'name' => $metaData['name'],
-                    'labelNames' => array(),
+                    'labelNames' => [],
                     'labelValues' => $this->decodeLabelValues($labelValues),
-                    'value' => $this->fromInteger($value['value'])
-                );
+                    'value' => $this->fromInteger($value['value']),
+                ];
             }
 
             $this->sortSamples($data['samples']);
@@ -216,23 +224,23 @@ private function collectGauges()
     /**
      * @return array
      */
-    private function collectHistograms()
+    private function collectHistograms(): array
     {
-        $histograms = array();
+        $histograms = [];
         foreach (new APCUIterator('/^prom:histogram:.*:meta/') as $histogram) {
             $metaData = json_decode($histogram['value'], true);
-            $data = array(
+            $data = [
                 'name' => $metaData['name'],
                 'help' => $metaData['help'],
                 'type' => $metaData['type'],
                 'labelNames' => $metaData['labelNames'],
-                'buckets' => $metaData['buckets']
-            );
+                'buckets' => $metaData['buckets'],
+            ];
 
             // Add the Inf bucket so we can compute it later on
             $data['buckets'][] = '+Inf';
 
-            $histogramBuckets = array();
+            $histogramBuckets = [];
             foreach (new APCUIterator('/^prom:histogram:' . $metaData['name'] . ':.*:value/') as $value) {
                 $parts = explode(':', $value['key']);
                 $labelValues = $parts[3];
@@ -248,40 +256,40 @@ private function collectHistograms()
                 $acc = 0;
                 $decodedLabelValues = $this->decodeLabelValues($labelValues);
                 foreach ($data['buckets'] as $bucket) {
-                    $bucket = (string) $bucket;
+                    $bucket = (string)$bucket;
                     if (!isset($histogramBuckets[$labelValues][$bucket])) {
-                        $data['samples'][] = array(
+                        $data['samples'][] = [
                             'name' => $metaData['name'] . '_bucket',
-                            'labelNames' => array('le'),
-                            'labelValues' => array_merge($decodedLabelValues, array($bucket)),
-                            'value' => $acc
-                        );
+                            'labelNames' => ['le'],
+                            'labelValues' => array_merge($decodedLabelValues, [$bucket]),
+                            'value' => $acc,
+                        ];
                     } else {
                         $acc += $histogramBuckets[$labelValues][$bucket];
-                        $data['samples'][] = array(
+                        $data['samples'][] = [
                             'name' => $metaData['name'] . '_' . 'bucket',
-                            'labelNames' => array('le'),
-                            'labelValues' => array_merge($decodedLabelValues, array($bucket)),
-                            'value' => $acc
-                        );
+                            'labelNames' => ['le'],
+                            'labelValues' => array_merge($decodedLabelValues, [$bucket]),
+                            'value' => $acc,
+                        ];
                     }
                 }
 
                 // Add the count
-                $data['samples'][] = array(
+                $data['samples'][] = [
                     'name' => $metaData['name'] . '_count',
-                    'labelNames' => array(),
+                    'labelNames' => [],
                     'labelValues' => $decodedLabelValues,
-                    'value' => $acc
-                );
+                    'value' => $acc,
+                ];
 
                 // Add the sum
-                $data['samples'][] = array(
+                $data['samples'][] = [
                     'name' => $metaData['name'] . '_sum',
-                    'labelNames' => array(),
+                    'labelNames' => [],
                     'labelValues' => $decodedLabelValues,
-                    'value' => $this->fromInteger($histogramBuckets[$labelValues]['sum'])
-                );
+                    'value' => $this->fromInteger($histogramBuckets[$labelValues]['sum']),
+                ];
 
             }
             $histograms[] = new MetricFamilySamples($data);
@@ -293,16 +301,16 @@ private function collectHistograms()
      * @param mixed $val
      * @return int
      */
-    private function toInteger($val)
+    private function toInteger($val): int
     {
         return unpack('Q', pack('d', $val))[1];
     }
 
     /**
      * @param mixed $val
-     * @return int
+     * @return float
      */
-    private function fromInteger($val)
+    private function fromInteger($val): float
     {
         return unpack('d', pack('Q', $val))[1];
     }
@@ -310,11 +318,14 @@ private function fromInteger($val)
     /**
      * @param array $samples
      */
-    private function sortSamples(array &$samples)
+    private function sortSamples(array &$samples): void
     {
-        usort($samples, function($a, $b){
-            return strcmp(implode("", $a['labelValues']), implode("", $b['labelValues']));
-        });
+        usort(
+            $samples,
+            function ($a, $b) {
+                return strcmp(implode("", $a['labelValues']), implode("", $b['labelValues']));
+            }
+        );
     }
 
     /**
@@ -322,7 +333,7 @@ private function sortSamples(array &$samples)
      * @return string
      * @throws RuntimeException
      */
-    private function encodeLabelValues(array $values)
+    private function encodeLabelValues(array $values): string
     {
         $json = json_encode($values);
         if (false === $json) {
@@ -336,7 +347,7 @@ private function encodeLabelValues(array $values)
      * @return array
      * @throws RuntimeException
      */
-    private function decodeLabelValues($values)
+    private function decodeLabelValues($values): array
     {
         $json = base64_decode($values, true);
         if (false === $json) {
diff --git a/src/Prometheus/Storage/Adapter.php b/src/Prometheus/Storage/Adapter.php
index e280f13..03f258e 100644
--- a/src/Prometheus/Storage/Adapter.php
+++ b/src/Prometheus/Storage/Adapter.php
@@ -1,9 +1,9 @@
 <?php
+declare(strict_types = 1);
+
 namespace Prometheus\Storage;
 
-use Prometheus\Collector;
 use Prometheus\MetricFamilySamples;
-use Prometheus\Sample;
 
 interface Adapter
 {
@@ -16,9 +16,21 @@ interface Adapter
      */
     public function collect();
 
-    public function updateHistogram(array $data);
+    /**
+     * @param array $data
+     * @return void
+     */
+    public function updateHistogram(array $data): void;
 
-    public function updateGauge(array $data);
+    /**
+     * @param array $data
+     * @return void
+     */
+    public function updateGauge(array $data): void;
 
-    public function updateCounter(array $data);
+    /**
+     * @param array $data
+     * @return void
+     */
+    public function updateCounter(array $data): void;
 }
diff --git a/src/Prometheus/Storage/InMemory.php b/src/Prometheus/Storage/InMemory.php
index 1c56de7..49ae4db 100644
--- a/src/Prometheus/Storage/InMemory.php
+++ b/src/Prometheus/Storage/InMemory.php
@@ -1,8 +1,8 @@
 <?php
+declare(strict_types=1);
 
 namespace Prometheus\Storage;
 
-
 use Prometheus\MetricFamilySamples;
 use RuntimeException;
 
@@ -16,7 +16,7 @@ class InMemory implements Adapter
     /**
      * @return MetricFamilySamples[]
      */
-    public function collect()
+    public function collect(): array
     {
         $metrics = $this->internalCollect($this->counters);
         $metrics = array_merge($metrics, $this->internalCollect($this->gauges));
@@ -24,7 +24,7 @@ public function collect()
         return $metrics;
     }
 
-    public function flushMemory()
+    public function flushMemory(): void
     {
         $this->counters = [];
         $this->gauges = [];
@@ -34,7 +34,7 @@ public function flushMemory()
     /**
      * @return array
      */
-    private function collectHistograms()
+    private function collectHistograms(): array
     {
         $histograms = [];
         foreach ($this->histograms as $histogram) {
@@ -44,7 +44,7 @@ private function collectHistograms()
                 'help' => $metaData['help'],
                 'type' => $metaData['type'],
                 'labelNames' => $metaData['labelNames'],
-                'buckets' => $metaData['buckets']
+                'buckets' => $metaData['buckets'],
             ];
 
             // Add the Inf bucket so we can compute it later on
@@ -72,7 +72,7 @@ private function collectHistograms()
                             'name' => $metaData['name'] . '_bucket',
                             'labelNames' => ['le'],
                             'labelValues' => array_merge($decodedLabelValues, [$bucket]),
-                            'value' => $acc
+                            'value' => $acc,
                         ];
                     } else {
                         $acc += $histogramBuckets[$labelValues][$bucket];
@@ -80,7 +80,7 @@ private function collectHistograms()
                             'name' => $metaData['name'] . '_' . 'bucket',
                             'labelNames' => ['le'],
                             'labelValues' => array_merge($decodedLabelValues, [$bucket]),
-                            'value' => $acc
+                            'value' => $acc,
                         ];
                     }
                 }
@@ -90,7 +90,7 @@ private function collectHistograms()
                     'name' => $metaData['name'] . '_count',
                     'labelNames' => [],
                     'labelValues' => $decodedLabelValues,
-                    'value' => $acc
+                    'value' => $acc,
                 ];
 
                 // Add the sum
@@ -98,7 +98,7 @@ private function collectHistograms()
                     'name' => $metaData['name'] . '_sum',
                     'labelNames' => [],
                     'labelValues' => $decodedLabelValues,
-                    'value' => $histogramBuckets[$labelValues]['sum']
+                    'value' => $histogramBuckets[$labelValues]['sum'],
                 ];
 
             }
@@ -111,7 +111,7 @@ private function collectHistograms()
      * @param array $metrics
      * @return array
      */
-    private function internalCollect(array $metrics)
+    private function internalCollect(array $metrics): array
     {
         $result = [];
         foreach ($metrics as $metric) {
@@ -129,7 +129,7 @@ private function internalCollect(array $metrics)
                     'name' => $metaData['name'],
                     'labelNames' => [],
                     'labelValues' => $this->decodeLabelValues($labelValues),
-                    'value' => $value
+                    'value' => $value,
                 ];
             }
             $this->sortSamples($data['samples']);
@@ -140,15 +140,16 @@ private function internalCollect(array $metrics)
 
     /**
      * @param array $data
+     * @return void
      */
-    public function updateHistogram(array $data)
+    public function updateHistogram(array $data): void
     {
         // Initialize the sum
         $metaKey = $this->metaKey($data);
         if (array_key_exists($metaKey, $this->histograms) === false) {
             $this->histograms[$metaKey] = [
                 'meta' => $this->metaData($data),
-                'samples' => []
+                'samples' => [],
             ];
         }
         $sumKey = $this->histogramBucketValueKey($data, 'sum');
@@ -177,14 +178,14 @@ public function updateHistogram(array $data)
     /**
      * @param array $data
      */
-    public function updateGauge(array $data)
+    public function updateGauge(array $data): void
     {
         $metaKey = $this->metaKey($data);
         $valueKey = $this->valueKey($data);
         if (array_key_exists($metaKey, $this->gauges) === false) {
             $this->gauges[$metaKey] = [
                 'meta' => $this->metaData($data),
-                'samples' => []
+                'samples' => [],
             ];
         }
         if (array_key_exists($valueKey, $this->gauges[$metaKey]['samples']) === false) {
@@ -200,14 +201,14 @@ public function updateGauge(array $data)
     /**
      * @param array $data
      */
-    public function updateCounter(array $data)
+    public function updateCounter(array $data): void
     {
         $metaKey = $this->metaKey($data);
         $valueKey = $this->valueKey($data);
         if (array_key_exists($metaKey, $this->counters) === false) {
             $this->counters[$metaKey] = [
                 'meta' => $this->metaData($data),
-                'samples' => []
+                'samples' => [],
             ];
         }
         if (array_key_exists($valueKey, $this->counters[$metaKey]['samples']) === false) {
@@ -225,14 +226,17 @@ public function updateCounter(array $data)
      * @param string $bucket
      * @return string
      */
-    private function histogramBucketValueKey(array $data, $bucket)
+    private function histogramBucketValueKey(array $data, $bucket): string
     {
-        return implode(':', [
-            $data['type'],
-            $data['name'],
-            $this->encodeLabelValues($data['labelValues']),
-            $bucket
-        ]);
+        return implode(
+            ':',
+            [
+                $data['type'],
+                $data['name'],
+                $this->encodeLabelValues($data['labelValues']),
+                $bucket,
+            ]
+        );
     }
 
     /**
@@ -240,7 +244,7 @@ private function histogramBucketValueKey(array $data, $bucket)
      *
      * @return string
      */
-    private function metaKey(array $data)
+    private function metaKey(array $data): string
     {
         return implode(':', [$data['type'], $data['name'], 'meta']);
     }
@@ -250,10 +254,12 @@ private function metaKey(array $data)
      *
      * @return string
      */
-    private function valueKey(array $data)
+    private function valueKey(array $data): string
     {
-        return implode(':',
-            [$data['type'], $data['name'], $this->encodeLabelValues($data['labelValues']), 'value']);
+        return implode(
+            ':',
+            [$data['type'], $data['name'], $this->encodeLabelValues($data['labelValues']), 'value']
+        );
     }
 
     /**
@@ -261,7 +267,7 @@ private function valueKey(array $data)
      *
      * @return array
      */
-    private function metaData(array $data)
+    private function metaData(array $data): array
     {
         $metricsMetaData = $data;
         unset($metricsMetaData['value']);
@@ -273,11 +279,14 @@ private function metaData(array $data)
     /**
      * @param array $samples
      */
-    private function sortSamples(array &$samples)
+    private function sortSamples(array &$samples): void
     {
-        usort($samples, function ($a, $b) {
-            return strcmp(implode("", $a['labelValues']), implode("", $b['labelValues']));
-        });
+        usort(
+            $samples,
+            function ($a, $b) {
+                return strcmp(implode("", $a['labelValues']), implode("", $b['labelValues']));
+            }
+        );
     }
 
     /**
@@ -285,7 +294,7 @@ private function sortSamples(array &$samples)
      * @return string
      * @throws RuntimeException
      */
-    private function encodeLabelValues(array $values)
+    private function encodeLabelValues(array $values): string
     {
         $json = json_encode($values);
         if (false === $json) {
@@ -299,7 +308,7 @@ private function encodeLabelValues(array $values)
      * @return array
      * @throws RuntimeException
      */
-    private function decodeLabelValues($values)
+    private function decodeLabelValues($values): array
     {
         $json = base64_decode($values, true);
         if (false === $json) {
diff --git a/src/Prometheus/Storage/Redis.php b/src/Prometheus/Storage/Redis.php
index 5babba0..1d46d88 100644
--- a/src/Prometheus/Storage/Redis.php
+++ b/src/Prometheus/Storage/Redis.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 namespace Prometheus\Storage;
 
 use InvalidArgumentException;
@@ -16,7 +18,7 @@ class Redis implements Adapter
     /**
      * @var array
      */
-    private static $defaultOptions = array();
+    private static $defaultOptions = [];
 
     /**
      * @var string
@@ -37,7 +39,7 @@ class Redis implements Adapter
      * Redis constructor.
      * @param array $options
      */
-    public function __construct(array $options = array())
+    public function __construct(array $options = [])
     {
         // with php 5.3 we cannot initialize the options directly on the field definition
         // so we initialize them here for now
@@ -67,7 +69,7 @@ public function __construct(array $options = array())
     /**
      * @param array $options
      */
-    public static function setDefaultOptions(array $options)
+    public static function setDefaultOptions(array $options): void
     {
         self::$defaultOptions = array_merge(self::$defaultOptions, $options);
     }
@@ -75,7 +77,7 @@ public static function setDefaultOptions(array $options)
     /**
      * @param $prefix
      */
-    public static function setPrefix($prefix)
+    public static function setPrefix($prefix): void
     {
         self::$prefix = $prefix;
     }
@@ -83,7 +85,7 @@ public static function setPrefix($prefix)
     /**
      * @throws StorageException
      */
-    public function flushRedis()
+    public function flushRedis(): void
     {
         $this->openConnection();
         $this->redis->flushAll();
@@ -93,7 +95,7 @@ public function flushRedis()
      * @return MetricFamilySamples[]
      * @throws StorageException
      */
-    public function collect()
+    public function collect(): array
     {
         $this->openConnection();
         $metrics = $this->collectHistograms();
@@ -110,25 +112,40 @@ function (array $metric) {
     /**
      * @throws StorageException
      */
-    private function openConnection()
+    private function openConnection(): void
+    {
+        $connectionStatus = $this->connectToServer();
+        if ($connectionStatus === false) {
+            throw new StorageException("Can't connect to Redis server", 0);
+        }
+
+        if ($this->options['password']) {
+            $this->redis->auth($this->options['password']);
+        }
+        if (isset($this->options['database'])) {
+            $this->redis->select($this->options['database']);
+        }
+
+        $this->redis->setOption(\Redis::OPT_READ_TIMEOUT, $this->options['read_timeout']);
+    }
+
+    /**
+     * @return bool
+     */
+    private function connectToServer(): bool
     {
         try {
             if ($this->options['persistent_connections']) {
-                @$this->redis->pconnect($this->options['host'], $this->options['port'], $this->options['timeout']);
-            } else {
-                @$this->redis->connect($this->options['host'], $this->options['port'], $this->options['timeout']);
-            }
-            if ($this->options['password']) {
-                $this->redis->auth($this->options['password']);
-            }
-            if (isset($this->options['database'])) {
-                $this->redis->select($this->options['database']);
+                return $this->redis->pconnect(
+                    $this->options['host'],
+                    $this->options['port'],
+                    $this->options['timeout']
+                );
             }
 
-            $this->redis->setOption(\Redis::OPT_READ_TIMEOUT, $this->options['read_timeout']);
-            
-        } catch (RedisException $e) {
-            throw new StorageException("Can't connect to Redis server", 0, $e);
+            return $this->redis->connect($this->options['host'], $this->options['port'], $this->options['timeout']);
+        } catch (\RedisException $e) {
+            return false;
         }
     }
 
@@ -136,7 +153,7 @@ private function openConnection()
      * @param array $data
      * @throws StorageException
      */
-    public function updateHistogram(array $data)
+    public function updateHistogram(array $data): void
     {
         $this->openConnection();
         $bucketToIncrease = '+Inf';
@@ -149,7 +166,8 @@ public function updateHistogram(array $data)
         $metaData = $data;
         unset($metaData['value']);
         unset($metaData['labelValues']);
-        $this->redis->eval(<<<LUA
+        $this->redis->eval(
+            <<<LUA
 local increment = redis.call('hIncrByFloat', KEYS[1], KEYS[2], ARGV[1])
 redis.call('hIncrBy', KEYS[1], KEYS[3], 1)
 if increment == ARGV[1] then
@@ -158,14 +176,14 @@ public function updateHistogram(array $data)
 end
 LUA
             ,
-            array(
+            [
                 $this->toMetricKey($data),
-                json_encode(array('b' => 'sum', 'labelValues' => $data['labelValues'])),
-                json_encode(array('b' => $bucketToIncrease, 'labelValues' => $data['labelValues'])),
+                json_encode(['b' => 'sum', 'labelValues' => $data['labelValues']]),
+                json_encode(['b' => $bucketToIncrease, 'labelValues' => $data['labelValues']]),
                 self::$prefix . Histogram::TYPE . self::PROMETHEUS_METRIC_KEYS_SUFFIX,
                 $data['value'],
                 json_encode($metaData),
-            ),
+            ],
             4
         );
     }
@@ -174,14 +192,15 @@ public function updateHistogram(array $data)
      * @param array $data
      * @throws StorageException
      */
-    public function updateGauge(array $data)
+    public function updateGauge(array $data): void
     {
         $this->openConnection();
         $metaData = $data;
         unset($metaData['value']);
         unset($metaData['labelValues']);
         unset($metaData['command']);
-        $this->redis->eval(<<<LUA
+        $this->redis->eval(
+            <<<LUA
 local result = redis.call(KEYS[2], KEYS[1], KEYS[4], ARGV[1])
 
 if KEYS[2] == 'hSet' then
@@ -197,31 +216,31 @@ public function updateGauge(array $data)
 end
 LUA
             ,
-            array(
+            [
                 $this->toMetricKey($data),
                 $this->getRedisCommand($data['command']),
                 self::$prefix . Gauge::TYPE . self::PROMETHEUS_METRIC_KEYS_SUFFIX,
                 json_encode($data['labelValues']),
                 $data['value'],
                 json_encode($metaData),
-            ),
+            ],
             4
         );
     }
 
     /**
      * @param array $data
-     * @return mixed
      * @throws StorageException
      */
-    public function updateCounter(array $data)
+    public function updateCounter(array $data): void
     {
         $this->openConnection();
         $metaData = $data;
         unset($metaData['value']);
         unset($metaData['labelValues']);
         unset($metaData['command']);
-        $result = $this->redis->eval(<<<LUA
+        $this->redis->eval(
+            <<<LUA
 local result = redis.call(KEYS[2], KEYS[1], KEYS[4], ARGV[1])
 if result == tonumber(ARGV[1]) then
     redis.call('hMSet', KEYS[1], '__meta', ARGV[2])
@@ -230,37 +249,36 @@ public function updateCounter(array $data)
 return result
 LUA
             ,
-            array(
+            [
                 $this->toMetricKey($data),
                 $this->getRedisCommand($data['command']),
                 self::$prefix . Counter::TYPE . self::PROMETHEUS_METRIC_KEYS_SUFFIX,
                 json_encode($data['labelValues']),
                 $data['value'],
                 json_encode($metaData),
-            ),
+            ],
             4
         );
-        return $result;
     }
 
     /**
      * @return array
      */
-    private function collectHistograms()
+    private function collectHistograms(): array
     {
         $keys = $this->redis->sMembers(self::$prefix . Histogram::TYPE . self::PROMETHEUS_METRIC_KEYS_SUFFIX);
         sort($keys);
-        $histograms = array();
+        $histograms = [];
         foreach ($keys as $key) {
             $raw = $this->redis->hGetAll($key);
             $histogram = json_decode($raw['__meta'], true);
             unset($raw['__meta']);
-            $histogram['samples'] = array();
+            $histogram['samples'] = [];
 
             // Add the Inf bucket so we can compute it later on
             $histogram['buckets'][] = '+Inf';
 
-            $allLabelValues = array();
+            $allLabelValues = [];
             foreach (array_keys($raw) as $k) {
                 $d = json_decode($k, true);
                 if ($d['b'] == 'sum') {
@@ -280,40 +298,40 @@ private function collectHistograms()
                 // the previous one.
                 $acc = 0;
                 foreach ($histogram['buckets'] as $bucket) {
-                    $bucketKey = json_encode(array('b' => $bucket, 'labelValues' => $labelValues));
+                    $bucketKey = json_encode(['b' => $bucket, 'labelValues' => $labelValues]);
                     if (!isset($raw[$bucketKey])) {
-                        $histogram['samples'][] = array(
+                        $histogram['samples'][] = [
                             'name' => $histogram['name'] . '_bucket',
-                            'labelNames' => array('le'),
-                            'labelValues' => array_merge($labelValues, array($bucket)),
-                            'value' => $acc
-                        );
+                            'labelNames' => ['le'],
+                            'labelValues' => array_merge($labelValues, [$bucket]),
+                            'value' => $acc,
+                        ];
                     } else {
                         $acc += $raw[$bucketKey];
-                        $histogram['samples'][] = array(
+                        $histogram['samples'][] = [
                             'name' => $histogram['name'] . '_bucket',
-                            'labelNames' => array('le'),
-                            'labelValues' => array_merge($labelValues, array($bucket)),
-                            'value' => $acc
-                        );
+                            'labelNames' => ['le'],
+                            'labelValues' => array_merge($labelValues, [$bucket]),
+                            'value' => $acc,
+                        ];
                     }
                 }
 
                 // Add the count
-                $histogram['samples'][] = array(
+                $histogram['samples'][] = [
                     'name' => $histogram['name'] . '_count',
-                    'labelNames' => array(),
+                    'labelNames' => [],
                     'labelValues' => $labelValues,
-                    'value' => $acc
-                );
+                    'value' => $acc,
+                ];
 
                 // Add the sum
-                $histogram['samples'][] = array(
+                $histogram['samples'][] = [
                     'name' => $histogram['name'] . '_sum',
-                    'labelNames' => array(),
+                    'labelNames' => [],
                     'labelValues' => $labelValues,
-                    'value' => $raw[json_encode(array('b' => 'sum', 'labelValues' => $labelValues))]
-                );
+                    'value' => $raw[json_encode(['b' => 'sum', 'labelValues' => $labelValues])],
+                ];
             }
             $histograms[] = $histogram;
         }
@@ -323,27 +341,30 @@ private function collectHistograms()
     /**
      * @return array
      */
-    private function collectGauges()
+    private function collectGauges(): array
     {
         $keys = $this->redis->sMembers(self::$prefix . Gauge::TYPE . self::PROMETHEUS_METRIC_KEYS_SUFFIX);
         sort($keys);
-        $gauges = array();
+        $gauges = [];
         foreach ($keys as $key) {
             $raw = $this->redis->hGetAll($key);
             $gauge = json_decode($raw['__meta'], true);
             unset($raw['__meta']);
-            $gauge['samples'] = array();
+            $gauge['samples'] = [];
             foreach ($raw as $k => $value) {
-                $gauge['samples'][] = array(
+                $gauge['samples'][] = [
                     'name' => $gauge['name'],
-                    'labelNames' => array(),
+                    'labelNames' => [],
                     'labelValues' => json_decode($k, true),
-                    'value' => $value
-                );
+                    'value' => $value,
+                ];
             }
-            usort($gauge['samples'], function($a, $b){
-                return strcmp(implode("", $a['labelValues']), implode("", $b['labelValues']));
-            });
+            usort(
+                $gauge['samples'],
+                function ($a, $b) {
+                    return strcmp(implode("", $a['labelValues']), implode("", $b['labelValues']));
+                }
+            );
             $gauges[] = $gauge;
         }
         return $gauges;
@@ -352,27 +373,30 @@ private function collectGauges()
     /**
      * @return array
      */
-    private function collectCounters()
+    private function collectCounters(): array
     {
         $keys = $this->redis->sMembers(self::$prefix . Counter::TYPE . self::PROMETHEUS_METRIC_KEYS_SUFFIX);
         sort($keys);
-        $counters = array();
+        $counters = [];
         foreach ($keys as $key) {
             $raw = $this->redis->hGetAll($key);
             $counter = json_decode($raw['__meta'], true);
             unset($raw['__meta']);
-            $counter['samples'] = array();
+            $counter['samples'] = [];
             foreach ($raw as $k => $value) {
-                $counter['samples'][] = array(
+                $counter['samples'][] = [
                     'name' => $counter['name'],
-                    'labelNames' => array(),
+                    'labelNames' => [],
                     'labelValues' => json_decode($k, true),
-                    'value' => $value
-                );
+                    'value' => $value,
+                ];
             }
-            usort($counter['samples'], function($a, $b){
-                return strcmp(implode("", $a['labelValues']), implode("", $b['labelValues']));
-            });
+            usort(
+                $counter['samples'],
+                function ($a, $b) {
+                    return strcmp(implode("", $a['labelValues']), implode("", $b['labelValues']));
+                }
+            );
             $counters[] = $counter;
         }
         return $counters;
@@ -382,7 +406,7 @@ private function collectCounters()
      * @param string $cmd
      * @return string
      */
-    private function getRedisCommand($cmd)
+    private function getRedisCommand($cmd): string
     {
         switch ($cmd) {
             case Adapter::COMMAND_INCREMENT_INTEGER:
@@ -400,9 +424,8 @@ private function getRedisCommand($cmd)
      * @param array $data
      * @return string
      */
-    private function toMetricKey(array $data)
+    private function toMetricKey(array $data): string
     {
-        return implode(':', array(self::$prefix, $data['type'], $data['name']));
+        return implode(':', [self::$prefix, $data['type'], $data['name']]);
     }
-
 }
diff --git a/tests/Test/BlackBoxPushGatewayTest.php b/tests/Test/BlackBoxPushGatewayTest.php
index 5453f43..47469be 100644
--- a/tests/Test/BlackBoxPushGatewayTest.php
+++ b/tests/Test/BlackBoxPushGatewayTest.php
@@ -23,7 +23,7 @@ public function pushGatewayShouldWork()
         $counter->incBy(6, ['blue']);
 
         $pushGateway = new PushGateway('pushgateway:9091');
-        $pushGateway->push($registry, 'my_job', array('instance' => 'foo'));
+        $pushGateway->push($registry, 'my_job', ['instance' => 'foo']);
 
         $httpClient = new Client();
         $metrics = $httpClient->get("http://pushgateway:9091/metrics")->getBody()->getContents();
@@ -34,7 +34,7 @@ public function pushGatewayShouldWork()
             $metrics
         );
 
-        $pushGateway->delete('my_job', array('instance' => 'foo'));
+        $pushGateway->delete('my_job', ['instance' => 'foo']);
 
         $httpClient = new Client();
         $metrics = $httpClient->get("http://pushgateway:9091/metrics")->getBody()->getContents();
diff --git a/tests/Test/Prometheus/AbstractCollectorRegistryTest.php b/tests/Test/Prometheus/AbstractCollectorRegistryTest.php
index 766c993..82d9b64 100644
--- a/tests/Test/Prometheus/AbstractCollectorRegistryTest.php
+++ b/tests/Test/Prometheus/AbstractCollectorRegistryTest.php
@@ -6,8 +6,6 @@
 
 use PHPUnit\Framework\TestCase;
 use Prometheus\CollectorRegistry;
-use Prometheus\Exception\MetricNotFoundException;
-use Prometheus\Exception\MetricsRegistrationException;
 use Prometheus\Histogram;
 use Prometheus\RenderTextFormat;
 use Prometheus\Storage\Adapter;
@@ -38,17 +36,18 @@ public function itShouldSaveGauges()
     {
         $registry = new CollectorRegistry($this->adapter);
 
-        $g = $registry->registerGauge('test', 'some_metric', 'this is for testing', array('foo'));
-        $g->set(35, array('bbb'));
-        $g->set(35, array('ddd'));
-        $g->set(35, array('aaa'));
-        $g->set(35, array('ccc'));
+        $g = $registry->registerGauge('test', 'some_metric', 'this is for testing', ['foo']);
+        $g->set(35, ['bbb']);
+        $g->set(35, ['ddd']);
+        $g->set(35, ['aaa']);
+        $g->set(35, ['ccc']);
 
 
         $registry = new CollectorRegistry($this->adapter);
         $this->assertThat(
             $this->renderer->render($registry->getMetricFamilySamples()),
-            $this->equalTo(<<<EOF
+            $this->equalTo(
+                <<<EOF
 # HELP test_some_metric this is for testing
 # TYPE test_some_metric gauge
 test_some_metric{foo="aaa"} 35
@@ -67,15 +66,16 @@ public function itShouldSaveGauges()
     public function itShouldSaveCounters()
     {
         $registry = new CollectorRegistry($this->adapter);
-        $metric = $registry->registerCounter('test', 'some_metric', 'this is for testing', array('foo', 'bar'));
-        $metric->incBy(2, array('lalal', 'lululu'));
-        $registry->getCounter('test', 'some_metric', array('foo', 'bar'))->inc(array('lalal', 'lululu'));
-        $registry->getCounter('test', 'some_metric', array('foo', 'bar'))->inc(array('lalal', 'lvlvlv'));
+        $metric = $registry->registerCounter('test', 'some_metric', 'this is for testing', ['foo', 'bar']);
+        $metric->incBy(2, ['lalal', 'lululu']);
+        $registry->getCounter('test', 'some_metric', ['foo', 'bar'])->inc(['lalal', 'lululu']);
+        $registry->getCounter('test', 'some_metric', ['foo', 'bar'])->inc(['lalal', 'lvlvlv']);
 
         $registry = new CollectorRegistry($this->adapter);
         $this->assertThat(
             $this->renderer->render($registry->getMetricFamilySamples()),
-            $this->equalTo(<<<EOF
+            $this->equalTo(
+                <<<EOF
 # HELP test_some_metric this is for testing
 # TYPE test_some_metric counter
 test_some_metric{foo="lalal",bar="lululu"} 3
@@ -92,17 +92,24 @@ public function itShouldSaveCounters()
     public function itShouldSaveHistograms()
     {
         $registry = new CollectorRegistry($this->adapter);
-        $metric = $registry->registerHistogram('test', 'some_metric', 'this is for testing', array('foo', 'bar'), array(0.1, 1, 5, 10));
-        $metric->observe(2, array('lalal', 'lululu'));
-        $registry->getHistogram('test', 'some_metric', array('foo', 'bar'))->observe(7.1, array('lalal', 'lvlvlv'));
-        $registry->getHistogram('test', 'some_metric', array('foo', 'bar'))->observe(13, array('lalal', 'lululu'));
-        $registry->getHistogram('test', 'some_metric', array('foo', 'bar'))->observe(7.1, array('lalal', 'lululu'));
-        $registry->getHistogram('test', 'some_metric', array('foo', 'bar'))->observe(7.1, array('gnaaha', 'hihihi'));
+        $metric = $registry->registerHistogram(
+            'test',
+            'some_metric',
+            'this is for testing',
+            ['foo', 'bar'],
+            [0.1, 1, 5, 10]
+        );
+        $metric->observe(2, ['lalal', 'lululu']);
+        $registry->getHistogram('test', 'some_metric', ['foo', 'bar'])->observe(7.1, ['lalal', 'lvlvlv']);
+        $registry->getHistogram('test', 'some_metric', ['foo', 'bar'])->observe(13, ['lalal', 'lululu']);
+        $registry->getHistogram('test', 'some_metric', ['foo', 'bar'])->observe(7.1, ['lalal', 'lululu']);
+        $registry->getHistogram('test', 'some_metric', ['foo', 'bar'])->observe(7.1, ['gnaaha', 'hihihi']);
 
         $registry = new CollectorRegistry($this->adapter);
         $this->assertThat(
             $this->renderer->render($registry->getMetricFamilySamples()),
-            $this->equalTo(<<<EOF
+            $this->equalTo(
+                <<<EOF
 # HELP test_some_metric this is for testing
 # TYPE test_some_metric histogram
 test_some_metric_bucket{foo="gnaaha",bar="hihihi",le="0.1"} 0
@@ -146,7 +153,8 @@ public function itShouldSaveHistogramsWithoutLabels()
         $registry = new CollectorRegistry($this->adapter);
         $this->assertThat(
             $this->renderer->render($registry->getMetricFamilySamples()),
-            $this->equalTo(<<<EOF
+            $this->equalTo(
+                <<<EOF
 # HELP test_some_metric this is for testing
 # TYPE test_some_metric histogram
 test_some_metric_bucket{le="0.005"} 0
@@ -177,14 +185,16 @@ public function itShouldSaveHistogramsWithoutLabels()
      */
     public function itShouldIncreaseACounterWithoutNamespace()
     {
-        $registry = new CollectorRegistry( $this->adapter);
+        $registry = new CollectorRegistry($this->adapter);
         $registry
             ->registerCounter('', 'some_quick_counter', 'just a quick measurement')
-            ->inc();
+            ->inc()
+        ;
 
         $this->assertThat(
             $this->renderer->render($registry->getMetricFamilySamples()),
-            $this->equalTo(<<<EOF
+            $this->equalTo(
+                <<<EOF
 # HELP some_quick_counter just a quick measurement
 # TYPE some_quick_counter counter
 some_quick_counter 1
@@ -200,7 +210,7 @@ public function itShouldIncreaseACounterWithoutNamespace()
      */
     public function itShouldForbidRegisteringTheSameCounterTwice()
     {
-        $registry = new CollectorRegistry( $this->adapter);
+        $registry = new CollectorRegistry($this->adapter);
         $registry->registerCounter('foo', 'metric', 'help');
         $registry->registerCounter('foo', 'metric', 'help');
     }
@@ -211,9 +221,9 @@ public function itShouldForbidRegisteringTheSameCounterTwice()
      */
     public function itShouldForbidRegisteringTheSameCounterWithDifferentLabels()
     {
-        $registry = new CollectorRegistry( $this->adapter);
-        $registry->registerCounter('foo', 'metric', 'help', array("foo", "bar"));
-        $registry->registerCounter('foo', 'metric', 'help', array("spam", "eggs"));
+        $registry = new CollectorRegistry($this->adapter);
+        $registry->registerCounter('foo', 'metric', 'help', ["foo", "bar"]);
+        $registry->registerCounter('foo', 'metric', 'help', ["spam", "eggs"]);
     }
 
     /**
@@ -222,7 +232,7 @@ public function itShouldForbidRegisteringTheSameCounterWithDifferentLabels()
      */
     public function itShouldForbidRegisteringTheSameHistogramTwice()
     {
-        $registry = new CollectorRegistry( $this->adapter);
+        $registry = new CollectorRegistry($this->adapter);
         $registry->registerHistogram('foo', 'metric', 'help');
         $registry->registerHistogram('foo', 'metric', 'help');
     }
@@ -233,9 +243,9 @@ public function itShouldForbidRegisteringTheSameHistogramTwice()
      */
     public function itShouldForbidRegisteringTheSameHistogramWithDifferentLabels()
     {
-        $registry = new CollectorRegistry( $this->adapter);
-        $registry->registerCounter('foo', 'metric', 'help', array("foo", "bar"));
-        $registry->registerCounter('foo', 'metric', 'help', array("spam", "eggs"));
+        $registry = new CollectorRegistry($this->adapter);
+        $registry->registerCounter('foo', 'metric', 'help', ["foo", "bar"]);
+        $registry->registerCounter('foo', 'metric', 'help', ["spam", "eggs"]);
     }
 
     /**
@@ -244,7 +254,7 @@ public function itShouldForbidRegisteringTheSameHistogramWithDifferentLabels()
      */
     public function itShouldForbidRegisteringTheSameGaugeTwice()
     {
-        $registry = new CollectorRegistry( $this->adapter);
+        $registry = new CollectorRegistry($this->adapter);
         $registry->registerGauge('foo', 'metric', 'help');
         $registry->registerGauge('foo', 'metric', 'help');
     }
@@ -255,9 +265,9 @@ public function itShouldForbidRegisteringTheSameGaugeTwice()
      */
     public function itShouldForbidRegisteringTheSameGaugeWithDifferentLabels()
     {
-        $registry = new CollectorRegistry( $this->adapter);
-        $registry->registerGauge('foo', 'metric', 'help', array("foo", "bar"));
-        $registry->registerGauge('foo', 'metric', 'help', array("spam", "eggs"));
+        $registry = new CollectorRegistry($this->adapter);
+        $registry->registerGauge('foo', 'metric', 'help', ["foo", "bar"]);
+        $registry->registerGauge('foo', 'metric', 'help', ["spam", "eggs"]);
     }
 
     /**
@@ -266,7 +276,7 @@ public function itShouldForbidRegisteringTheSameGaugeWithDifferentLabels()
      */
     public function itShouldThrowAnExceptionWhenGettingANonExistentMetric()
     {
-        $registry = new CollectorRegistry( $this->adapter);
+        $registry = new CollectorRegistry($this->adapter);
         $registry->getGauge("not_here", "go_away");
     }
 
diff --git a/tests/Test/Prometheus/AbstractCounterTest.php b/tests/Test/Prometheus/AbstractCounterTest.php
index 3487c0d..d96b71e 100644
--- a/tests/Test/Prometheus/AbstractCounterTest.php
+++ b/tests/Test/Prometheus/AbstractCounterTest.php
@@ -25,36 +25,38 @@ public function setUp()
         $this->configureAdapter();
     }
 
+    public abstract function configureAdapter();
+
     /**
      * @test
      */
     public function itShouldIncreaseWithLabels()
     {
-        $gauge = new Counter($this->adapter, 'test', 'some_metric', 'this is for testing', array('foo', 'bar'));
-        $gauge->inc(array('lalal', 'lululu'));
-        $gauge->inc(array('lalal', 'lululu'));
-        $gauge->inc(array('lalal', 'lululu'));
+        $gauge = new Counter($this->adapter, 'test', 'some_metric', 'this is for testing', ['foo', 'bar']);
+        $gauge->inc(['lalal', 'lululu']);
+        $gauge->inc(['lalal', 'lululu']);
+        $gauge->inc(['lalal', 'lululu']);
         $this->assertThat(
             $this->adapter->collect(),
             $this->equalTo(
-                array(
+                [
                     new MetricFamilySamples(
-                        array(
+                        [
                             'type' => Counter::TYPE,
                             'help' => 'this is for testing',
                             'name' => 'test_some_metric',
-                            'labelNames' => array('foo', 'bar'),
-                            'samples' => array(
-                                array(
-                                    'labelValues' => array('lalal', 'lululu'),
+                            'labelNames' => ['foo', 'bar'],
+                            'samples' => [
+                                [
+                                    'labelValues' => ['lalal', 'lululu'],
                                     'value' => 3,
                                     'name' => 'test_some_metric',
-                                    'labelNames' => array()
-                                ),
-                            )
-                        )
-                    )
-                )
+                                    'labelNames' => [],
+                                ],
+                            ],
+                        ]
+                    ),
+                ]
             )
         );
     }
@@ -69,24 +71,24 @@ public function itShouldIncreaseWithoutLabelWhenNoLabelsAreDefined()
         $this->assertThat(
             $this->adapter->collect(),
             $this->equalTo(
-                array(
+                [
                     new MetricFamilySamples(
-                        array(
+                        [
                             'type' => Counter::TYPE,
                             'help' => 'this is for testing',
                             'name' => 'test_some_metric',
-                            'labelNames' => array(),
-                            'samples' => array(
-                                array(
-                                    'labelValues' => array(),
+                            'labelNames' => [],
+                            'samples' => [
+                                [
+                                    'labelValues' => [],
                                     'value' => 1,
                                     'name' => 'test_some_metric',
-                                    'labelNames' => array()
-                                ),
-                            )
-                        )
-                    )
-                )
+                                    'labelNames' => [],
+                                ],
+                            ],
+                        ]
+                    ),
+                ]
             )
         );
     }
@@ -96,30 +98,30 @@ public function itShouldIncreaseWithoutLabelWhenNoLabelsAreDefined()
      */
     public function itShouldIncreaseTheCounterByAnArbitraryInteger()
     {
-        $gauge = new Counter($this->adapter, 'test', 'some_metric', 'this is for testing', array('foo', 'bar'));
-        $gauge->inc(array('lalal', 'lululu'));
-        $gauge->incBy(123, array('lalal', 'lululu'));
+        $gauge = new Counter($this->adapter, 'test', 'some_metric', 'this is for testing', ['foo', 'bar']);
+        $gauge->inc(['lalal', 'lululu']);
+        $gauge->incBy(123, ['lalal', 'lululu']);
         $this->assertThat(
             $this->adapter->collect(),
             $this->equalTo(
-                array(
+                [
                     new MetricFamilySamples(
-                        array(
+                        [
                             'type' => Counter::TYPE,
                             'help' => 'this is for testing',
                             'name' => 'test_some_metric',
-                            'labelNames' => array('foo', 'bar'),
-                            'samples' => array(
-                                array(
-                                    'labelValues' => array('lalal', 'lululu'),
+                            'labelNames' => ['foo', 'bar'],
+                            'samples' => [
+                                [
+                                    'labelValues' => ['lalal', 'lululu'],
                                     'value' => 124,
                                     'name' => 'test_some_metric',
-                                    'labelNames' => array()
-                                ),
-                            )
-                        )
-                    )
-                )
+                                    'labelNames' => [],
+                                ],
+                            ],
+                        ]
+                    ),
+                ]
             )
         );
     }
@@ -139,7 +141,7 @@ public function itShouldRejectInvalidMetricsNames()
      */
     public function itShouldRejectInvalidLabelNames()
     {
-        new Counter($this->adapter, 'test', 'some_metric', 'help', array('invalid label'));
+        new Counter($this->adapter, 'test', 'some_metric', 'help', ['invalid label']);
     }
 
     /**
@@ -151,8 +153,8 @@ public function itShouldRejectInvalidLabelNames()
     public function isShouldAcceptAnySequenceOfBasicLatinCharactersForLabelValues($value)
     {
         $label = 'foo';
-        $histogram = new Counter($this->adapter, 'test', 'some_metric', 'help', array($label));
-        $histogram->inc(array($value));
+        $histogram = new Counter($this->adapter, 'test', 'some_metric', 'help', [$label]);
+        $histogram->inc([$value]);
 
         $metrics = $this->adapter->collect();
         self::assertInternalType('array', $metrics);
@@ -173,8 +175,8 @@ public function isShouldAcceptAnySequenceOfBasicLatinCharactersForLabelValues($v
     }
 
     /**
-     * @see isShouldAcceptArbitraryLabelValues
      * @return array
+     * @see isShouldAcceptArbitraryLabelValues
      */
     public function labelValuesDataProvider()
     {
@@ -182,10 +184,8 @@ public function labelValuesDataProvider()
         // Basic Latin
         // See https://en.wikipedia.org/wiki/List_of_Unicode_characters#Basic_Latin
         for ($i = 32; $i <= 121; $i++) {
-            $cases['ASCII code ' . $i] = array(chr($i));
+            $cases['ASCII code ' . $i] = [chr($i)];
         }
         return $cases;
     }
-
-    public abstract function configureAdapter();
 }
diff --git a/tests/Test/Prometheus/AbstractGaugeTest.php b/tests/Test/Prometheus/AbstractGaugeTest.php
index 32c2673..4536f48 100644
--- a/tests/Test/Prometheus/AbstractGaugeTest.php
+++ b/tests/Test/Prometheus/AbstractGaugeTest.php
@@ -25,34 +25,36 @@ public function setUp()
         $this->configureAdapter();
     }
 
+    public abstract function configureAdapter();
+
     /**
      * @test
      */
     public function itShouldAllowSetWithLabels()
     {
-        $gauge = new Gauge($this->adapter, 'test', 'some_metric', 'this is for testing', array('foo', 'bar'));
-        $gauge->set(123, array('lalal', 'lululu'));
+        $gauge = new Gauge($this->adapter, 'test', 'some_metric', 'this is for testing', ['foo', 'bar']);
+        $gauge->set(123, ['lalal', 'lululu']);
         $this->assertThat(
             $this->adapter->collect(),
             $this->equalTo(
-                array(
+                [
                     new MetricFamilySamples(
-                        array(
+                        [
                             'name' => 'test_some_metric',
                             'help' => 'this is for testing',
                             'type' => Gauge::TYPE,
-                            'labelNames' => array('foo', 'bar'),
-                            'samples' => array(
-                                array(
+                            'labelNames' => ['foo', 'bar'],
+                            'samples' => [
+                                [
                                     'name' => 'test_some_metric',
-                                    'labelNames' => array(),
-                                    'labelValues' => array('lalal', 'lululu'),
+                                    'labelNames' => [],
+                                    'labelValues' => ['lalal', 'lululu'],
                                     'value' => 123,
-                                )
-                            )
-                        )
-                    )
-                )
+                                ],
+                            ],
+                        ]
+                    ),
+                ]
             )
         );
         $this->assertThat($gauge->getHelp(), $this->equalTo('this is for testing'));
@@ -69,24 +71,24 @@ public function itShouldAllowSetWithoutLabelWhenNoLabelsAreDefined()
         $this->assertThat(
             $this->adapter->collect(),
             $this->equalTo(
-                array(
+                [
                     new MetricFamilySamples(
-                        array(
+                        [
                             'name' => 'test_some_metric',
                             'help' => 'this is for testing',
                             'type' => Gauge::TYPE,
-                            'labelNames' => array(),
-                            'samples' => array(
-                                array(
+                            'labelNames' => [],
+                            'samples' => [
+                                [
                                     'name' => 'test_some_metric',
-                                    'labelNames' => array(),
-                                    'labelValues' => array(),
+                                    'labelNames' => [],
+                                    'labelValues' => [],
                                     'value' => 123,
-                                )
-                            )
-                        )
-                    )
-                )
+                                ],
+                            ],
+                        ]
+                    ),
+                ]
             )
         );
         $this->assertThat($gauge->getHelp(), $this->equalTo('this is for testing'));
@@ -103,24 +105,24 @@ public function itShouldAllowSetWithAFloatValue()
         $this->assertThat(
             $this->adapter->collect(),
             $this->equalTo(
-                array(
+                [
                     new MetricFamilySamples(
-                        array(
+                        [
                             'name' => 'test_some_metric',
                             'help' => 'this is for testing',
                             'type' => Gauge::TYPE,
-                            'labelNames' => array(),
-                            'samples' => array(
-                                array(
+                            'labelNames' => [],
+                            'samples' => [
+                                [
                                     'name' => 'test_some_metric',
-                                    'labelNames' => array(),
-                                    'labelValues' => array(),
+                                    'labelNames' => [],
+                                    'labelValues' => [],
                                     'value' => 123.5,
-                                )
-                            )
-                        )
-                    )
-                )
+                                ],
+                            ],
+                        ]
+                    ),
+                ]
             )
         );
         $this->assertThat($gauge->getHelp(), $this->equalTo('this is for testing'));
@@ -132,30 +134,30 @@ public function itShouldAllowSetWithAFloatValue()
      */
     public function itShouldIncrementAValue()
     {
-        $gauge = new Gauge($this->adapter, 'test', 'some_metric', 'this is for testing', array('foo', 'bar'));
-        $gauge->inc(array('lalal', 'lululu'));
-        $gauge->incBy(123, array('lalal', 'lululu'));
+        $gauge = new Gauge($this->adapter, 'test', 'some_metric', 'this is for testing', ['foo', 'bar']);
+        $gauge->inc(['lalal', 'lululu']);
+        $gauge->incBy(123, ['lalal', 'lululu']);
         $this->assertThat(
             $this->adapter->collect(),
             $this->equalTo(
-                array(
+                [
                     new MetricFamilySamples(
-                        array(
+                        [
                             'name' => 'test_some_metric',
                             'help' => 'this is for testing',
                             'type' => Gauge::TYPE,
-                            'labelNames' => array('foo', 'bar'),
-                            'samples' => array(
-                                array(
+                            'labelNames' => ['foo', 'bar'],
+                            'samples' => [
+                                [
                                     'name' => 'test_some_metric',
-                                    'labelNames' => array(),
-                                    'labelValues' => array('lalal', 'lululu'),
+                                    'labelNames' => [],
+                                    'labelValues' => ['lalal', 'lululu'],
                                     'value' => 124,
-                                )
-                            )
-                        )
-                    )
-                )
+                                ],
+                            ],
+                        ]
+                    ),
+                ]
             )
         );
     }
@@ -165,30 +167,30 @@ public function itShouldIncrementAValue()
      */
     public function itShouldIncrementWithFloatValue()
     {
-        $gauge = new Gauge($this->adapter, 'test', 'some_metric', 'this is for testing', array('foo', 'bar'));
-        $gauge->inc(array('lalal', 'lululu'));
-        $gauge->incBy(123.5, array('lalal', 'lululu'));
+        $gauge = new Gauge($this->adapter, 'test', 'some_metric', 'this is for testing', ['foo', 'bar']);
+        $gauge->inc(['lalal', 'lululu']);
+        $gauge->incBy(123.5, ['lalal', 'lululu']);
         $this->assertThat(
             $this->adapter->collect(),
             $this->equalTo(
-                array(
+                [
                     new MetricFamilySamples(
-                        array(
+                        [
                             'name' => 'test_some_metric',
                             'help' => 'this is for testing',
                             'type' => Gauge::TYPE,
-                            'labelNames' => array('foo', 'bar'),
-                            'samples' => array(
-                                array(
+                            'labelNames' => ['foo', 'bar'],
+                            'samples' => [
+                                [
                                     'name' => 'test_some_metric',
-                                    'labelNames' => array(),
-                                    'labelValues' => array('lalal', 'lululu'),
+                                    'labelNames' => [],
+                                    'labelValues' => ['lalal', 'lululu'],
                                     'value' => 124.5,
-                                )
-                            )
-                        )
-                    )
-                )
+                                ],
+                            ],
+                        ]
+                    ),
+                ]
             )
         );
     }
@@ -198,30 +200,30 @@ public function itShouldIncrementWithFloatValue()
      */
     public function itShouldDecrementAValue()
     {
-        $gauge = new Gauge($this->adapter, 'test', 'some_metric', 'this is for testing', array('foo', 'bar'));
-        $gauge->dec(array('lalal', 'lululu'));
-        $gauge->decBy(123, array('lalal', 'lululu'));
+        $gauge = new Gauge($this->adapter, 'test', 'some_metric', 'this is for testing', ['foo', 'bar']);
+        $gauge->dec(['lalal', 'lululu']);
+        $gauge->decBy(123, ['lalal', 'lululu']);
         $this->assertThat(
             $this->adapter->collect(),
             $this->equalTo(
-                array(
+                [
                     new MetricFamilySamples(
-                        array(
+                        [
                             'name' => 'test_some_metric',
                             'help' => 'this is for testing',
                             'type' => Gauge::TYPE,
-                            'labelNames' => array('foo', 'bar'),
-                            'samples' => array(
-                                array(
+                            'labelNames' => ['foo', 'bar'],
+                            'samples' => [
+                                [
                                     'name' => 'test_some_metric',
-                                    'labelNames' => array(),
-                                    'labelValues' => array('lalal', 'lululu'),
+                                    'labelNames' => [],
+                                    'labelValues' => ['lalal', 'lululu'],
                                     'value' => -124,
-                                )
-                            )
-                        )
-                    )
-                )
+                                ],
+                            ],
+                        ]
+                    ),
+                ]
             )
         );
     }
@@ -231,30 +233,30 @@ public function itShouldDecrementAValue()
      */
     public function itShouldDecrementWithFloatValue()
     {
-        $gauge = new Gauge($this->adapter, 'test', 'some_metric', 'this is for testing', array('foo', 'bar'));
-        $gauge->dec(array('lalal', 'lululu'));
-        $gauge->decBy(123, array('lalal', 'lululu'));
+        $gauge = new Gauge($this->adapter, 'test', 'some_metric', 'this is for testing', ['foo', 'bar']);
+        $gauge->dec(['lalal', 'lululu']);
+        $gauge->decBy(123, ['lalal', 'lululu']);
         $this->assertThat(
             $this->adapter->collect(),
             $this->equalTo(
-                array(
+                [
                     new MetricFamilySamples(
-                        array(
+                        [
                             'name' => 'test_some_metric',
                             'help' => 'this is for testing',
                             'type' => Gauge::TYPE,
-                            'labelNames' => array('foo', 'bar'),
-                            'samples' => array(
-                                array(
+                            'labelNames' => ['foo', 'bar'],
+                            'samples' => [
+                                [
                                     'name' => 'test_some_metric',
-                                    'labelNames' => array(),
-                                    'labelValues' => array('lalal', 'lululu'),
+                                    'labelNames' => [],
+                                    'labelValues' => ['lalal', 'lululu'],
                                     'value' => -124,
-                                )
-                            )
-                        )
-                    )
-                )
+                                ],
+                            ],
+                        ]
+                    ),
+                ]
             )
         );
     }
@@ -264,30 +266,30 @@ public function itShouldDecrementWithFloatValue()
      */
     public function itShouldOverwriteWhenSettingTwice()
     {
-        $gauge = new Gauge($this->adapter, 'test', 'some_metric', 'this is for testing', array('foo', 'bar'));
-        $gauge->set(123, array('lalal', 'lululu'));
-        $gauge->set(321, array('lalal', 'lululu'));
+        $gauge = new Gauge($this->adapter, 'test', 'some_metric', 'this is for testing', ['foo', 'bar']);
+        $gauge->set(123, ['lalal', 'lululu']);
+        $gauge->set(321, ['lalal', 'lululu']);
         $this->assertThat(
             $this->adapter->collect(),
             $this->equalTo(
-                array(
+                [
                     new MetricFamilySamples(
-                        array(
+                        [
                             'name' => 'test_some_metric',
                             'help' => 'this is for testing',
                             'type' => Gauge::TYPE,
-                            'labelNames' => array('foo', 'bar'),
-                            'samples' => array(
-                                array(
+                            'labelNames' => ['foo', 'bar'],
+                            'samples' => [
+                                [
                                     'name' => 'test_some_metric',
-                                    'labelNames' => array(),
-                                    'labelValues' => array('lalal', 'lululu'),
+                                    'labelNames' => [],
+                                    'labelValues' => ['lalal', 'lululu'],
                                     'value' => 321,
-                                )
-                            )
-                        )
-                    )
-                )
+                                ],
+                            ],
+                        ]
+                    ),
+                ]
             )
         );
     }
@@ -307,7 +309,7 @@ public function itShouldRejectInvalidMetricsNames()
      */
     public function itShouldRejectInvalidLabelNames()
     {
-        new Gauge($this->adapter, 'test', 'some_metric', 'help', array('invalid label'));
+        new Gauge($this->adapter, 'test', 'some_metric', 'help', ['invalid label']);
     }
 
     /**
@@ -319,8 +321,8 @@ public function itShouldRejectInvalidLabelNames()
     public function isShouldAcceptAnySequenceOfBasicLatinCharactersForLabelValues($value)
     {
         $label = 'foo';
-        $histogram = new Gauge($this->adapter, 'test', 'some_metric', 'help', array($label));
-        $histogram->inc(array($value));
+        $histogram = new Gauge($this->adapter, 'test', 'some_metric', 'help', [$label]);
+        $histogram->inc([$value]);
 
         $metrics = $this->adapter->collect();
         self::assertInternalType('array', $metrics);
@@ -341,8 +343,8 @@ public function isShouldAcceptAnySequenceOfBasicLatinCharactersForLabelValues($v
     }
 
     /**
-     * @see isShouldAcceptArbitraryLabelValues
      * @return array
+     * @see isShouldAcceptArbitraryLabelValues
      */
     public function labelValuesDataProvider()
     {
@@ -350,10 +352,8 @@ public function labelValuesDataProvider()
         // Basic Latin
         // See https://en.wikipedia.org/wiki/List_of_Unicode_characters#Basic_Latin
         for ($i = 32; $i <= 121; $i++) {
-            $cases['ASCII code ' . $i] = array(chr($i));
+            $cases['ASCII code ' . $i] = [chr($i)];
         }
         return $cases;
     }
-
-    public abstract function configureAdapter();
 }
diff --git a/tests/Test/Prometheus/AbstractHistogramTest.php b/tests/Test/Prometheus/AbstractHistogramTest.php
index af982d5..c64d2d8 100644
--- a/tests/Test/Prometheus/AbstractHistogramTest.php
+++ b/tests/Test/Prometheus/AbstractHistogramTest.php
@@ -26,6 +26,8 @@ public function setUp()
         $this->configureAdapter();
     }
 
+    public abstract function configureAdapter();
+
     /**
      * @test
      */
@@ -36,62 +38,62 @@ public function itShouldObserveWithLabels()
             'test',
             'some_metric',
             'this is for testing',
-            array('foo', 'bar'),
-            array(100, 200, 300)
+            ['foo', 'bar'],
+            [100, 200, 300]
         );
-        $histogram->observe(123, array('lalal', 'lululu'));
-        $histogram->observe(245, array('lalal', 'lululu'));
+        $histogram->observe(123, ['lalal', 'lululu']);
+        $histogram->observe(245, ['lalal', 'lululu']);
         $this->assertThat(
             $this->adapter->collect(),
             $this->equalTo(
-                array(
+                [
                     new MetricFamilySamples(
-                        array(
+                        [
                             'name' => 'test_some_metric',
                             'help' => 'this is for testing',
                             'type' => Histogram::TYPE,
-                            'labelNames' => array('foo', 'bar'),
-                            'samples' => array(
-                                array(
+                            'labelNames' => ['foo', 'bar'],
+                            'samples' => [
+                                [
                                     'name' => 'test_some_metric_bucket',
-                                    'labelNames' => array('le'),
-                                    'labelValues' => array('lalal', 'lululu', 100),
+                                    'labelNames' => ['le'],
+                                    'labelValues' => ['lalal', 'lululu', 100],
                                     'value' => 0,
-                                ),
-                                array(
+                                ],
+                                [
                                     'name' => 'test_some_metric_bucket',
-                                    'labelNames' => array('le'),
-                                    'labelValues' => array('lalal', 'lululu', 200),
+                                    'labelNames' => ['le'],
+                                    'labelValues' => ['lalal', 'lululu', 200],
                                     'value' => 1,
-                                ),
-                                array(
+                                ],
+                                [
                                     'name' => 'test_some_metric_bucket',
-                                    'labelNames' => array('le'),
-                                    'labelValues' => array('lalal', 'lululu', 300),
+                                    'labelNames' => ['le'],
+                                    'labelValues' => ['lalal', 'lululu', 300],
                                     'value' => 2,
-                                ),
-                                array(
+                                ],
+                                [
                                     'name' => 'test_some_metric_bucket',
-                                    'labelNames' => array('le'),
-                                    'labelValues' => array('lalal', 'lululu', '+Inf'),
+                                    'labelNames' => ['le'],
+                                    'labelValues' => ['lalal', 'lululu', '+Inf'],
                                     'value' => 2,
-                                ),
-                                array(
+                                ],
+                                [
                                     'name' => 'test_some_metric_count',
-                                    'labelNames' => array(),
-                                    'labelValues' => array('lalal', 'lululu'),
+                                    'labelNames' => [],
+                                    'labelValues' => ['lalal', 'lululu'],
                                     'value' => 2,
-                                ),
-                                array(
+                                ],
+                                [
                                     'name' => 'test_some_metric_sum',
-                                    'labelNames' => array(),
-                                    'labelValues' => array('lalal', 'lululu'),
+                                    'labelNames' => [],
+                                    'labelValues' => ['lalal', 'lululu'],
                                     'value' => 368,
-                                )
-                            )
-                        )
-                    )
-                )
+                                ],
+                            ],
+                        ]
+                    ),
+                ]
             )
         );
     }
@@ -106,61 +108,61 @@ public function itShouldObserveWithoutLabelWhenNoLabelsAreDefined()
             'test',
             'some_metric',
             'this is for testing',
-            array(),
-            array(100, 200, 300)
+            [],
+            [100, 200, 300]
         );
         $histogram->observe(245);
         $this->assertThat(
             $this->adapter->collect(),
             $this->equalTo(
-                array(
+                [
                     new MetricFamilySamples(
-                        array(
+                        [
                             'name' => 'test_some_metric',
                             'help' => 'this is for testing',
                             'type' => Histogram::TYPE,
-                            'labelNames' => array(),
-                            'samples' => array(
-                                array(
+                            'labelNames' => [],
+                            'samples' => [
+                                [
                                     'name' => 'test_some_metric_bucket',
-                                    'labelNames' => array('le'),
-                                    'labelValues' => array(100),
+                                    'labelNames' => ['le'],
+                                    'labelValues' => [100],
                                     'value' => 0,
-                                ),
-                                array(
+                                ],
+                                [
                                     'name' => 'test_some_metric_bucket',
-                                    'labelNames' => array('le'),
-                                    'labelValues' => array(200),
+                                    'labelNames' => ['le'],
+                                    'labelValues' => [200],
                                     'value' => 0,
-                                ),
-                                array(
+                                ],
+                                [
                                     'name' => 'test_some_metric_bucket',
-                                    'labelNames' => array('le'),
-                                    'labelValues' => array(300),
+                                    'labelNames' => ['le'],
+                                    'labelValues' => [300],
                                     'value' => 1,
-                                ),
-                                array(
+                                ],
+                                [
                                     'name' => 'test_some_metric_bucket',
-                                    'labelNames' => array('le'),
-                                    'labelValues' => array('+Inf'),
+                                    'labelNames' => ['le'],
+                                    'labelValues' => ['+Inf'],
                                     'value' => 1,
-                                ),
-                                array(
+                                ],
+                                [
                                     'name' => 'test_some_metric_count',
-                                    'labelNames' => array(),
-                                    'labelValues' => array(),
+                                    'labelNames' => [],
+                                    'labelValues' => [],
                                     'value' => 1,
-                                ),
-                                array(
+                                ],
+                                [
                                     'name' => 'test_some_metric_sum',
-                                    'labelNames' => array(),
-                                    'labelValues' => array(),
+                                    'labelNames' => [],
+                                    'labelValues' => [],
                                     'value' => 245,
-                                )
-                            )
-                        )
-                    )
-                )
+                                ],
+                            ],
+                        ]
+                    ),
+                ]
             )
         );
     }
@@ -175,62 +177,62 @@ public function itShouldObserveValuesOfTypeDouble()
             'test',
             'some_metric',
             'this is for testing',
-            array(),
-            array(0.1, 0.2, 0.3)
+            [],
+            [0.1, 0.2, 0.3]
         );
         $histogram->observe(0.11);
         $histogram->observe(0.3);
         $this->assertThat(
             $this->adapter->collect(),
             $this->equalTo(
-                array(
+                [
                     new MetricFamilySamples(
-                        array(
+                        [
                             'name' => 'test_some_metric',
                             'help' => 'this is for testing',
                             'type' => Histogram::TYPE,
-                            'labelNames' => array(),
-                            'samples' => array(
-                                array(
+                            'labelNames' => [],
+                            'samples' => [
+                                [
                                     'name' => 'test_some_metric_bucket',
-                                    'labelNames' => array('le'),
-                                    'labelValues' => array(0.1),
+                                    'labelNames' => ['le'],
+                                    'labelValues' => [0.1],
                                     'value' => 0,
-                                ),
-                                array(
+                                ],
+                                [
                                     'name' => 'test_some_metric_bucket',
-                                    'labelNames' => array('le'),
-                                    'labelValues' => array(0.2),
+                                    'labelNames' => ['le'],
+                                    'labelValues' => [0.2],
                                     'value' => 1,
-                                ),
-                                array(
+                                ],
+                                [
                                     'name' => 'test_some_metric_bucket',
-                                    'labelNames' => array('le'),
-                                    'labelValues' => array(0.3),
+                                    'labelNames' => ['le'],
+                                    'labelValues' => [0.3],
                                     'value' => 2,
-                                ),
-                                array(
+                                ],
+                                [
                                     'name' => 'test_some_metric_bucket',
-                                    'labelNames' => array('le'),
-                                    'labelValues' => array('+Inf'),
+                                    'labelNames' => ['le'],
+                                    'labelValues' => ['+Inf'],
                                     'value' => 2,
-                                ),
-                                array(
+                                ],
+                                [
                                     'name' => 'test_some_metric_count',
-                                    'labelNames' => array(),
-                                    'labelValues' => array(),
+                                    'labelNames' => [],
+                                    'labelValues' => [],
                                     'value' => 2,
-                                ),
-                                array(
+                                ],
+                                [
                                     'name' => 'test_some_metric_sum',
-                                    'labelNames' => array(),
-                                    'labelValues' => array(),
+                                    'labelNames' => [],
+                                    'labelValues' => [],
                                     'value' => 0.41,
-                                )
-                            )
-                        )
-                    )
-                )
+                                ],
+                            ],
+                        ]
+                    ),
+                ]
             )
         );
     }
@@ -247,7 +249,7 @@ public function itShouldProvideDefaultBuckets()
             'test',
             'some_metric',
             'this is for testing',
-            array()
+            []
 
         );
         $histogram->observe(0.11);
@@ -255,120 +257,120 @@ public function itShouldProvideDefaultBuckets()
         $this->assertThat(
             $this->adapter->collect(),
             $this->equalTo(
-                array(
+                [
                     new MetricFamilySamples(
-                        array(
+                        [
                             'name' => 'test_some_metric',
                             'help' => 'this is for testing',
                             'type' => Histogram::TYPE,
-                            'labelNames' => array(),
-                            'samples' => array(
-                                array(
+                            'labelNames' => [],
+                            'samples' => [
+                                [
                                     'name' => 'test_some_metric_bucket',
-                                    'labelNames' => array('le'),
-                                    'labelValues' => array(0.005),
+                                    'labelNames' => ['le'],
+                                    'labelValues' => [0.005],
                                     'value' => 0,
-                                ),
-                                array(
+                                ],
+                                [
                                     'name' => 'test_some_metric_bucket',
-                                    'labelNames' => array('le'),
-                                    'labelValues' => array(0.01),
+                                    'labelNames' => ['le'],
+                                    'labelValues' => [0.01],
                                     'value' => 0,
-                                ),
-                                array(
+                                ],
+                                [
                                     'name' => 'test_some_metric_bucket',
-                                    'labelNames' => array('le'),
-                                    'labelValues' => array(0.025),
+                                    'labelNames' => ['le'],
+                                    'labelValues' => [0.025],
                                     'value' => 0,
-                                ),
-                                array(
+                                ],
+                                [
                                     'name' => 'test_some_metric_bucket',
-                                    'labelNames' => array('le'),
-                                    'labelValues' => array(0.05),
+                                    'labelNames' => ['le'],
+                                    'labelValues' => [0.05],
                                     'value' => 1,
-                                ),
-                                array(
+                                ],
+                                [
                                     'name' => 'test_some_metric_bucket',
-                                    'labelNames' => array('le'),
-                                    'labelValues' => array(0.075),
+                                    'labelNames' => ['le'],
+                                    'labelValues' => [0.075],
                                     'value' => 1,
-                                ),
-                                array(
+                                ],
+                                [
                                     'name' => 'test_some_metric_bucket',
-                                    'labelNames' => array('le'),
-                                    'labelValues' => array(0.1),
+                                    'labelNames' => ['le'],
+                                    'labelValues' => [0.1],
                                     'value' => 1,
-                                ),
-                                array(
+                                ],
+                                [
                                     'name' => 'test_some_metric_bucket',
-                                    'labelNames' => array('le'),
-                                    'labelValues' => array(0.25),
+                                    'labelNames' => ['le'],
+                                    'labelValues' => [0.25],
                                     'value' => 2,
-                                ),
-                                array(
+                                ],
+                                [
                                     'name' => 'test_some_metric_bucket',
-                                    'labelNames' => array('le'),
-                                    'labelValues' => array(0.5),
+                                    'labelNames' => ['le'],
+                                    'labelValues' => [0.5],
                                     'value' => 2,
-                                ),
-                                array(
+                                ],
+                                [
                                     'name' => 'test_some_metric_bucket',
-                                    'labelNames' => array('le'),
-                                    'labelValues' => array(0.75),
+                                    'labelNames' => ['le'],
+                                    'labelValues' => [0.75],
                                     'value' => 2,
-                                ),
-                                array(
+                                ],
+                                [
                                     'name' => 'test_some_metric_bucket',
-                                    'labelNames' => array('le'),
-                                    'labelValues' => array(1.0),
+                                    'labelNames' => ['le'],
+                                    'labelValues' => [1.0],
                                     'value' => 2,
-                                ),
-                                array(
+                                ],
+                                [
                                     'name' => 'test_some_metric_bucket',
-                                    'labelNames' => array('le'),
-                                    'labelValues' => array(2.5),
+                                    'labelNames' => ['le'],
+                                    'labelValues' => [2.5],
                                     'value' => 2,
-                                ),
-                                array(
+                                ],
+                                [
                                     'name' => 'test_some_metric_bucket',
-                                    'labelNames' => array('le'),
-                                    'labelValues' => array(5),
+                                    'labelNames' => ['le'],
+                                    'labelValues' => [5],
                                     'value' => 2,
-                                ),
-                                array(
+                                ],
+                                [
                                     'name' => 'test_some_metric_bucket',
-                                    'labelNames' => array('le'),
-                                    'labelValues' => array(7.5),
+                                    'labelNames' => ['le'],
+                                    'labelValues' => [7.5],
                                     'value' => 2,
-                                ),
-                                array(
+                                ],
+                                [
                                     'name' => 'test_some_metric_bucket',
-                                    'labelNames' => array('le'),
-                                    'labelValues' => array(10),
+                                    'labelNames' => ['le'],
+                                    'labelValues' => [10],
                                     'value' => 2,
-                                ),
-                                array(
+                                ],
+                                [
                                     'name' => 'test_some_metric_bucket',
-                                    'labelNames' => array('le'),
-                                    'labelValues' => array('+Inf'),
+                                    'labelNames' => ['le'],
+                                    'labelValues' => ['+Inf'],
                                     'value' => 2,
-                                ),
-                                array(
+                                ],
+                                [
                                     'name' => 'test_some_metric_count',
-                                    'labelNames' => array(),
-                                    'labelValues' => array(),
+                                    'labelNames' => [],
+                                    'labelValues' => [],
                                     'value' => 2,
-                                ),
-                                array(
+                                ],
+                                [
                                     'name' => 'test_some_metric_sum',
-                                    'labelNames' => array(),
-                                    'labelValues' => array(),
+                                    'labelNames' => [],
+                                    'labelValues' => [],
                                     'value' => 0.14,
-                                )
-                            )
-                        )
-                    )
-                )
+                                ],
+                            ],
+                        ]
+                    ),
+                ]
             )
         );
     }
@@ -380,7 +382,7 @@ public function itShouldProvideDefaultBuckets()
      */
     public function itShouldThrowAnExceptionWhenTheBucketSizesAreNotIncreasing()
     {
-        new Histogram($this->adapter, 'test', 'some_metric', 'this is for testing', array(), array(1, 1));
+        new Histogram($this->adapter, 'test', 'some_metric', 'this is for testing', [], [1, 1]);
     }
 
     /**
@@ -390,7 +392,7 @@ public function itShouldThrowAnExceptionWhenTheBucketSizesAreNotIncreasing()
      */
     public function itShouldThrowAnExceptionWhenThereIsLessThanOneBucket()
     {
-        new Histogram($this->adapter, 'test', 'some_metric', 'this is for testing', array(), array());
+        new Histogram($this->adapter, 'test', 'some_metric', 'this is for testing', [], []);
     }
 
     /**
@@ -400,7 +402,7 @@ public function itShouldThrowAnExceptionWhenThereIsLessThanOneBucket()
      */
     public function itShouldThrowAnExceptionWhenThereIsALabelNamedLe()
     {
-        new Histogram($this->adapter, 'test', 'some_metric', 'this is for testing', array('le'), array(1));
+        new Histogram($this->adapter, 'test', 'some_metric', 'this is for testing', ['le'], [1]);
     }
 
     /**
@@ -410,7 +412,7 @@ public function itShouldThrowAnExceptionWhenThereIsALabelNamedLe()
      */
     public function itShouldRejectInvalidMetricsNames()
     {
-        new Histogram($this->adapter, 'test', 'some invalid metric', 'help', array(), array(1));
+        new Histogram($this->adapter, 'test', 'some invalid metric', 'help', [], [1]);
     }
 
     /**
@@ -420,7 +422,7 @@ public function itShouldRejectInvalidMetricsNames()
      */
     public function itShouldRejectInvalidLabelNames()
     {
-        new Histogram($this->adapter, 'test', 'some_metric', 'help', array('invalid label'), array(1));
+        new Histogram($this->adapter, 'test', 'some_metric', 'help', ['invalid label'], [1]);
     }
 
     /**
@@ -432,8 +434,8 @@ public function itShouldRejectInvalidLabelNames()
     public function isShouldAcceptAnySequenceOfBasicLatinCharactersForLabelValues($value)
     {
         $label = 'foo';
-        $histogram = new Histogram($this->adapter, 'test', 'some_metric', 'help', array($label), array(1));
-        $histogram->observe(1, array($value));
+        $histogram = new Histogram($this->adapter, 'test', 'some_metric', 'help', [$label], [1]);
+        $histogram->observe(1, [$value]);
 
         $metrics = $this->adapter->collect();
         self::assertInternalType('array', $metrics);
@@ -454,8 +456,8 @@ public function isShouldAcceptAnySequenceOfBasicLatinCharactersForLabelValues($v
     }
 
     /**
-     * @see isShouldAcceptArbitraryLabelValues
      * @return array
+     * @see isShouldAcceptArbitraryLabelValues
      */
     public function labelValuesDataProvider()
     {
@@ -463,10 +465,8 @@ public function labelValuesDataProvider()
         // Basic Latin
         // See https://en.wikipedia.org/wiki/List_of_Unicode_characters#Basic_Latin
         for ($i = 32; $i <= 121; $i++) {
-            $cases['ASCII code ' . $i] = array(chr($i));
+            $cases['ASCII code ' . $i] = [chr($i)];
         }
         return $cases;
     }
-
-    public abstract function configureAdapter();
 }
diff --git a/tests/Test/Prometheus/Redis/CollectorRegistryTest.php b/tests/Test/Prometheus/Redis/CollectorRegistryTest.php
index 2e69ce9..b023e23 100644
--- a/tests/Test/Prometheus/Redis/CollectorRegistryTest.php
+++ b/tests/Test/Prometheus/Redis/CollectorRegistryTest.php
@@ -14,7 +14,7 @@ class CollectorRegistryTest extends AbstractCollectorRegistryTest
 {
     public function configureAdapter()
     {
-        $this->adapter = new Redis(array('host' => REDIS_HOST));
+        $this->adapter = new Redis(['host' => REDIS_HOST]);
         $this->adapter->flushRedis();
     }
 }
diff --git a/tests/Test/Prometheus/Redis/CounterTest.php b/tests/Test/Prometheus/Redis/CounterTest.php
index 088f9dd..2a59a7f 100644
--- a/tests/Test/Prometheus/Redis/CounterTest.php
+++ b/tests/Test/Prometheus/Redis/CounterTest.php
@@ -14,7 +14,7 @@ class CounterTest extends AbstractCounterTest
 {
     public function configureAdapter()
     {
-        $this->adapter = new Redis(array('host' => REDIS_HOST));
+        $this->adapter = new Redis(['host' => REDIS_HOST]);
         $this->adapter->flushRedis();
     }
 }
diff --git a/tests/Test/Prometheus/Redis/GaugeTest.php b/tests/Test/Prometheus/Redis/GaugeTest.php
index c359037..f5f363a 100644
--- a/tests/Test/Prometheus/Redis/GaugeTest.php
+++ b/tests/Test/Prometheus/Redis/GaugeTest.php
@@ -14,7 +14,7 @@ class GaugeTest extends AbstractGaugeTest
 {
     public function configureAdapter()
     {
-        $this->adapter = new Redis(array('host' => REDIS_HOST));
+        $this->adapter = new Redis(['host' => REDIS_HOST]);
         $this->adapter->flushRedis();
     }
 }
diff --git a/tests/Test/Prometheus/Redis/HistogramTest.php b/tests/Test/Prometheus/Redis/HistogramTest.php
index da15c25..806a348 100644
--- a/tests/Test/Prometheus/Redis/HistogramTest.php
+++ b/tests/Test/Prometheus/Redis/HistogramTest.php
@@ -14,7 +14,7 @@ class HistogramTest extends AbstractHistogramTest
 {
     public function configureAdapter()
     {
-        $this->adapter = new Redis(array('host' => REDIS_HOST));
+        $this->adapter = new Redis(['host' => REDIS_HOST]);
         $this->adapter->flushRedis();
     }
 }
diff --git a/tests/Test/Prometheus/Storage/RedisTest.php b/tests/Test/Prometheus/Storage/RedisTest.php
index dcaddba..9ba0c65 100644
--- a/tests/Test/Prometheus/Storage/RedisTest.php
+++ b/tests/Test/Prometheus/Storage/RedisTest.php
@@ -12,12 +12,13 @@ class RedisTest extends TestCase
 {
     /**
      * @test
-     * @expectedException StorageException
+     * @expectedException Prometheus\Exception\StorageException
      * @expectedExceptionMessage Can't connect to Redis server
      */
     public function itShouldThrowAnExceptionOnConnectionFailure()
     {
-        $redis = new Redis(['host' => 'completely.fake.example.test']);
+        $redis = new Redis(['host' => '/dev/null']);
+        $redis->collect();
         $redis->flushRedis();
     }
 

From 01405bc8254e35989ff5741dfb7d7f1234e9cc1f Mon Sep 17 00:00:00 2001
From: Daniel Noel-Davies <daniel.noel-davies@endclothing.com>
Date: Mon, 22 Jul 2019 10:24:08 +0100
Subject: [PATCH 06/28] Add missing typehints and format exception message a
 little nicer

---
 src/Prometheus/PushGateway.php      | 6 ++++--
 src/Prometheus/RenderTextFormat.php | 2 +-
 src/Prometheus/Storage/Redis.php    | 4 ++--
 3 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/src/Prometheus/PushGateway.php b/src/Prometheus/PushGateway.php
index e8792af..24b6401 100644
--- a/src/Prometheus/PushGateway.php
+++ b/src/Prometheus/PushGateway.php
@@ -91,8 +91,10 @@ private function doRequest(CollectorRegistry $collectorRegistry, string $job, ar
         $response = $client->request($method, $url, $requestOptions);
         $statusCode = $response->getStatusCode();
         if ($statusCode != 202) {
-            $msg = "Unexpected status code " . $statusCode . " received from push gateway " . $this->address . ": " . $response->getBody(
-                );
+            $msg = "Unexpected status code "
+                . $statusCode
+                . " received from push gateway "
+                . $this->address . ": " . $response->getBody();
             throw new RuntimeException($msg);
         }
     }
diff --git a/src/Prometheus/RenderTextFormat.php b/src/Prometheus/RenderTextFormat.php
index c0b3e70..1bbacf6 100644
--- a/src/Prometheus/RenderTextFormat.php
+++ b/src/Prometheus/RenderTextFormat.php
@@ -53,7 +53,7 @@ private function renderSample(MetricFamilySamples $metric, Sample $sample): stri
     }
 
     /**
-     * @param $v
+     * @param string $v
      * @return string
      */
     private function escapeLabelValue($v): string
diff --git a/src/Prometheus/Storage/Redis.php b/src/Prometheus/Storage/Redis.php
index 1d46d88..434aab2 100644
--- a/src/Prometheus/Storage/Redis.php
+++ b/src/Prometheus/Storage/Redis.php
@@ -403,10 +403,10 @@ function ($a, $b) {
     }
 
     /**
-     * @param string $cmd
+     * @param int $cmd
      * @return string
      */
-    private function getRedisCommand($cmd): string
+    private function getRedisCommand(int $cmd): string
     {
         switch ($cmd) {
             case Adapter::COMMAND_INCREMENT_INTEGER:

From 4d33aec98430c4e1bb76cd4737a5e3882b9132e1 Mon Sep 17 00:00:00 2001
From: Daniel Noel-Davies <daniel.noel-davies@endclothing.com>
Date: Mon, 22 Jul 2019 12:07:07 +0100
Subject: [PATCH 07/28] Use object property value declarations instead of using
 declarations within the constructor

---
 examples/flush_adapter.php       |  2 +-
 examples/metrics.php             |  2 +-
 examples/pushgateway.php         |  2 +-
 examples/some_counter.php        |  2 +-
 examples/some_gauge.php          |  2 +-
 examples/some_histogram.php      |  2 +-
 src/Prometheus/Storage/Redis.php | 34 ++++++++++----------------------
 7 files changed, 16 insertions(+), 30 deletions(-)

diff --git a/examples/flush_adapter.php b/examples/flush_adapter.php
index 028fdc7..08cd1e0 100644
--- a/examples/flush_adapter.php
+++ b/examples/flush_adapter.php
@@ -4,7 +4,7 @@
 $adapter = $_GET['adapter'];
 
 if ($adapter === 'redis') {
-    define('REDIS_HOST', isset($_SERVER['REDIS_HOST']) ? $_SERVER['REDIS_HOST'] : '127.0.0.1');
+    define('REDIS_HOST', $_SERVER['REDIS_HOST'] ?? '127.0.0.1');
 
     $redisAdapter = new Prometheus\Storage\Redis(['host' => REDIS_HOST]);
     $redisAdapter->flushRedis();
diff --git a/examples/metrics.php b/examples/metrics.php
index 74a111b..e523f79 100644
--- a/examples/metrics.php
+++ b/examples/metrics.php
@@ -9,7 +9,7 @@
 $adapter = $_GET['adapter'];
 
 if ($adapter === 'redis') {
-    Redis::setDefaultOptions(['host' => isset($_SERVER['REDIS_HOST']) ? $_SERVER['REDIS_HOST'] : '127.0.0.1']);
+    Redis::setDefaultOptions(['host' => $_SERVER['REDIS_HOST'] ?? '127.0.0.1']);
     $adapter = new Prometheus\Storage\Redis();
 } elseif ($adapter === 'apc') {
     $adapter = new Prometheus\Storage\APC();
diff --git a/examples/pushgateway.php b/examples/pushgateway.php
index e78706f..f850f5c 100644
--- a/examples/pushgateway.php
+++ b/examples/pushgateway.php
@@ -8,7 +8,7 @@
 $adapter = $_GET['adapter'];
 
 if ($adapter === 'redis') {
-    Redis::setDefaultOptions(['host' => isset($_SERVER['REDIS_HOST']) ? $_SERVER['REDIS_HOST'] : '127.0.0.1']);
+    Redis::setDefaultOptions(['host' => $_SERVER['REDIS_HOST'] ?? '127.0.0.1']);
     $adapter = new Prometheus\Storage\Redis();
 } elseif ($adapter === 'apc') {
     $adapter = new Prometheus\Storage\APC();
diff --git a/examples/some_counter.php b/examples/some_counter.php
index 71e7290..857e7e8 100644
--- a/examples/some_counter.php
+++ b/examples/some_counter.php
@@ -8,7 +8,7 @@
 $adapter = $_GET['adapter'];
 
 if ($adapter === 'redis') {
-    Redis::setDefaultOptions(['host' => isset($_SERVER['REDIS_HOST']) ? $_SERVER['REDIS_HOST'] : '127.0.0.1']);
+    Redis::setDefaultOptions(['host' => $_SERVER['REDIS_HOST'] ?? '127.0.0.1']);
     $adapter = new Prometheus\Storage\Redis();
 } elseif ($adapter === 'apc') {
     $adapter = new Prometheus\Storage\APC();
diff --git a/examples/some_gauge.php b/examples/some_gauge.php
index ca2180f..255362b 100644
--- a/examples/some_gauge.php
+++ b/examples/some_gauge.php
@@ -11,7 +11,7 @@
 $adapter = $_GET['adapter'];
 
 if ($adapter === 'redis') {
-    Redis::setDefaultOptions(['host' => isset($_SERVER['REDIS_HOST']) ? $_SERVER['REDIS_HOST'] : '127.0.0.1']);
+    Redis::setDefaultOptions(['host' => $_SERVER['REDIS_HOST'] ?? '127.0.0.1']);
     $adapter = new Prometheus\Storage\Redis();
 } elseif ($adapter === 'apc') {
     $adapter = new Prometheus\Storage\APC();
diff --git a/examples/some_histogram.php b/examples/some_histogram.php
index babbced..eaacb8a 100644
--- a/examples/some_histogram.php
+++ b/examples/some_histogram.php
@@ -10,7 +10,7 @@
 $adapter = $_GET['adapter'];
 
 if ($adapter === 'redis') {
-    Redis::setDefaultOptions(['host' => isset($_SERVER['REDIS_HOST']) ? $_SERVER['REDIS_HOST'] : '127.0.0.1']);
+    Redis::setDefaultOptions(['host' => $_SERVER['REDIS_HOST'] ?? '127.0.0.1']);
     $adapter = new Prometheus\Storage\Redis();
 } elseif ($adapter === 'apc') {
     $adapter = new Prometheus\Storage\APC();
diff --git a/src/Prometheus/Storage/Redis.php b/src/Prometheus/Storage/Redis.php
index 434aab2..7074c53 100644
--- a/src/Prometheus/Storage/Redis.php
+++ b/src/Prometheus/Storage/Redis.php
@@ -9,7 +9,6 @@
 use Prometheus\Gauge;
 use Prometheus\Histogram;
 use Prometheus\MetricFamilySamples;
-use RedisException;
 
 class Redis implements Adapter
 {
@@ -18,7 +17,14 @@ class Redis implements Adapter
     /**
      * @var array
      */
-    private static $defaultOptions = [];
+    private static $defaultOptions = [
+        'host' => '127.0.0.1',
+        'port' => 6379,
+        'timeout' => 0.1,
+        'read_timeout' => 10,
+        'persistent_connections' => false,
+        'password' => null,
+    ];
 
     /**
      * @var string
@@ -28,7 +34,7 @@ class Redis implements Adapter
     /**
      * @var array
      */
-    private $options;
+    private $options = [];
 
     /**
      * @var \Redis
@@ -41,27 +47,6 @@ class Redis implements Adapter
      */
     public function __construct(array $options = [])
     {
-        // with php 5.3 we cannot initialize the options directly on the field definition
-        // so we initialize them here for now
-        if (!isset(self::$defaultOptions['host'])) {
-            self::$defaultOptions['host'] = '127.0.0.1';
-        }
-        if (!isset(self::$defaultOptions['port'])) {
-            self::$defaultOptions['port'] = 6379;
-        }
-        if (!isset(self::$defaultOptions['timeout'])) {
-            self::$defaultOptions['timeout'] = 0.1; // in seconds
-        }
-        if (!isset(self::$defaultOptions['read_timeout'])) {
-            self::$defaultOptions['read_timeout'] = 10; // in seconds
-        }
-        if (!isset(self::$defaultOptions['persistent_connections'])) {
-            self::$defaultOptions['persistent_connections'] = false;
-        }
-        if (!isset(self::$defaultOptions['password'])) {
-            self::$defaultOptions['password'] = null;
-        }
-
         $this->options = array_merge(self::$defaultOptions, $options);
         $this->redis = new \Redis();
     }
@@ -122,6 +107,7 @@ private function openConnection(): void
         if ($this->options['password']) {
             $this->redis->auth($this->options['password']);
         }
+
         if (isset($this->options['database'])) {
             $this->redis->select($this->options['database']);
         }

From 6a644c37d9316dfa363149c615f13adfd2bd7fbc Mon Sep 17 00:00:00 2001
From: Daniel Noel-Davies <daniel.noel-davies@endclothing.com>
Date: Mon, 22 Jul 2019 12:13:08 +0100
Subject: [PATCH 08/28] Fix weird nesting issues

---
 src/Prometheus/RenderTextFormat.php |  9 ++----
 src/Prometheus/Storage/APC.php      | 45 ++++++++++++-----------------
 src/Prometheus/Storage/InMemory.php | 40 ++++++++++++-------------
 src/Prometheus/Storage/Redis.php    | 18 ++++--------
 4 files changed, 47 insertions(+), 65 deletions(-)

diff --git a/src/Prometheus/RenderTextFormat.php b/src/Prometheus/RenderTextFormat.php
index 1bbacf6..fcd0679 100644
--- a/src/Prometheus/RenderTextFormat.php
+++ b/src/Prometheus/RenderTextFormat.php
@@ -13,12 +13,9 @@ class RenderTextFormat
      */
     public function render(array $metrics): string
     {
-        usort(
-            $metrics,
-            function (MetricFamilySamples $a, MetricFamilySamples $b) {
-                return strcmp($a->getName(), $b->getName());
-            }
-        );
+        usort( $metrics, function (MetricFamilySamples $a, MetricFamilySamples $b) {
+            return strcmp($a->getName(), $b->getName());
+        });
 
         $lines = [];
 
diff --git a/src/Prometheus/Storage/APC.php b/src/Prometheus/Storage/APC.php
index e7a8864..397eb39 100644
--- a/src/Prometheus/Storage/APC.php
+++ b/src/Prometheus/Storage/APC.php
@@ -116,16 +116,13 @@ private function metaKey(array $data): string
      */
     private function valueKey(array $data): string
     {
-        return implode(
-            ':',
-            [
-                self::PROMETHEUS_PREFIX,
-                $data['type'],
-                $data['name'],
-                $this->encodeLabelValues($data['labelValues']),
-                'value',
-            ]
-        );
+        return implode(':', [
+            self::PROMETHEUS_PREFIX,
+            $data['type'],
+            $data['name'],
+            $this->encodeLabelValues($data['labelValues']),
+            'value',
+        ]);
     }
 
     /**
@@ -134,17 +131,14 @@ private function valueKey(array $data): string
      */
     private function histogramBucketValueKey(array $data, $bucket): string
     {
-        return implode(
-            ':',
-            [
-                self::PROMETHEUS_PREFIX,
-                $data['type'],
-                $data['name'],
-                $this->encodeLabelValues($data['labelValues']),
-                $bucket,
-                'value',
-            ]
-        );
+        return implode(':', [
+            self::PROMETHEUS_PREFIX,
+            $data['type'],
+            $data['name'],
+            $this->encodeLabelValues($data['labelValues']),
+            $bucket,
+            'value',
+        ]);
     }
 
     /**
@@ -320,12 +314,9 @@ private function fromInteger($val): float
      */
     private function sortSamples(array &$samples): void
     {
-        usort(
-            $samples,
-            function ($a, $b) {
-                return strcmp(implode("", $a['labelValues']), implode("", $b['labelValues']));
-            }
-        );
+        usort($samples, function ($a, $b) {
+            return strcmp(implode("", $a['labelValues']), implode("", $b['labelValues']));
+        });
     }
 
     /**
diff --git a/src/Prometheus/Storage/InMemory.php b/src/Prometheus/Storage/InMemory.php
index 49ae4db..35c48e1 100644
--- a/src/Prometheus/Storage/InMemory.php
+++ b/src/Prometheus/Storage/InMemory.php
@@ -228,15 +228,12 @@ public function updateCounter(array $data): void
      */
     private function histogramBucketValueKey(array $data, $bucket): string
     {
-        return implode(
-            ':',
-            [
-                $data['type'],
-                $data['name'],
-                $this->encodeLabelValues($data['labelValues']),
-                $bucket,
-            ]
-        );
+        return implode(':', [
+            $data['type'],
+            $data['name'],
+            $this->encodeLabelValues($data['labelValues']),
+            $bucket,
+        ]);
     }
 
     /**
@@ -246,7 +243,11 @@ private function histogramBucketValueKey(array $data, $bucket): string
      */
     private function metaKey(array $data): string
     {
-        return implode(':', [$data['type'], $data['name'], 'meta']);
+        return implode(':', [
+            $data['type'],
+            $data['name'],
+            'meta'
+        ]);
     }
 
     /**
@@ -256,10 +257,12 @@ private function metaKey(array $data): string
      */
     private function valueKey(array $data): string
     {
-        return implode(
-            ':',
-            [$data['type'], $data['name'], $this->encodeLabelValues($data['labelValues']), 'value']
-        );
+        return implode(':', [
+            $data['type'],
+            $data['name'],
+            $this->encodeLabelValues($data['labelValues']),
+            'value'
+        ]);
     }
 
     /**
@@ -281,12 +284,9 @@ private function metaData(array $data): array
      */
     private function sortSamples(array &$samples): void
     {
-        usort(
-            $samples,
-            function ($a, $b) {
-                return strcmp(implode("", $a['labelValues']), implode("", $b['labelValues']));
-            }
-        );
+        usort($samples, function ($a, $b) {
+            return strcmp(implode("", $a['labelValues']), implode("", $b['labelValues']));
+        });
     }
 
     /**
diff --git a/src/Prometheus/Storage/Redis.php b/src/Prometheus/Storage/Redis.php
index 7074c53..45f4566 100644
--- a/src/Prometheus/Storage/Redis.php
+++ b/src/Prometheus/Storage/Redis.php
@@ -345,12 +345,9 @@ private function collectGauges(): array
                     'value' => $value,
                 ];
             }
-            usort(
-                $gauge['samples'],
-                function ($a, $b) {
-                    return strcmp(implode("", $a['labelValues']), implode("", $b['labelValues']));
-                }
-            );
+            usort($gauge['samples'], function ($a, $b) {
+                return strcmp(implode("", $a['labelValues']), implode("", $b['labelValues']));
+            });
             $gauges[] = $gauge;
         }
         return $gauges;
@@ -377,12 +374,9 @@ private function collectCounters(): array
                     'value' => $value,
                 ];
             }
-            usort(
-                $counter['samples'],
-                function ($a, $b) {
-                    return strcmp(implode("", $a['labelValues']), implode("", $b['labelValues']));
-                }
-            );
+            usort($counter['samples'], function ($a, $b) {
+                return strcmp(implode("", $a['labelValues']), implode("", $b['labelValues']));
+            });
             $counters[] = $counter;
         }
         return $counters;

From 417d335d9aabe040aaafb4471ecb61b5cbddb0b6 Mon Sep 17 00:00:00 2001
From: Daniel Noel-Davies <daniel.noel-davies@endclothing.com>
Date: Mon, 22 Jul 2019 14:03:25 +0100
Subject: [PATCH 09/28] Fix autoloading with PSR-4

---
 composer.json | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/composer.json b/composer.json
index b941542..bce0026 100644
--- a/composer.json
+++ b/composer.json
@@ -23,8 +23,8 @@
         "ext-apc": "Required if using APCu."
     },
     "autoload": {
-        "psr-0": {
-            "Prometheus\\": "src/"
+        "psr-4": {
+            "Prometheus\\": "src/Prometheus/"
         }
     },
     "autoload-dev": {

From 9c40adca08f4da597c976317444bbb6543bfcea5 Mon Sep 17 00:00:00 2001
From: Daniel Noel-Davies <daniel.noel-davies@endclothing.com>
Date: Mon, 22 Jul 2019 14:14:54 +0100
Subject: [PATCH 10/28] Update README.md

---
 README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 2c62cd7..03e9e75 100644
--- a/README.md
+++ b/README.md
@@ -89,7 +89,7 @@ Also look at the [examples](examples).
 
 ### Dependencies
 
-* PHP 5.6
+* PHP 7.1
 * PHP Redis extension
 * PHP APCu extension
 * [Composer](https://getcomposer.org/doc/00-intro.md#installation-linux-unix-osx)

From 8c7fa911a53d2a3b9745a1f61ae19cf4e9ac772e Mon Sep 17 00:00:00 2001
From: Daniel Noel-Davies <daniel.noel-davies@endclothing.com>
Date: Tue, 23 Jul 2019 15:49:28 +0100
Subject: [PATCH 11/28] Removed unused namespaces

---
 tests/Test/BlackBoxPushGatewayTest.php                   | 1 -
 tests/Test/Prometheus/APC/CollectorRegistryTest.php      | 1 -
 tests/Test/Prometheus/APC/CounterTest.php                | 1 -
 tests/Test/Prometheus/APC/GaugeTest.php                  | 1 -
 tests/Test/Prometheus/APC/HistogramTest.php              | 1 -
 tests/Test/Prometheus/InMemory/CollectorRegistryTest.php | 1 -
 tests/Test/Prometheus/InMemory/CounterTest.php           | 1 -
 tests/Test/Prometheus/InMemory/GaugeTest.php             | 1 -
 tests/Test/Prometheus/InMemory/HistogramTest.php         | 1 -
 tests/Test/Prometheus/Redis/CollectorRegistryTest.php    | 2 --
 tests/Test/Prometheus/Redis/CounterTest.php              | 1 -
 tests/Test/Prometheus/Redis/GaugeTest.php                | 1 -
 tests/Test/Prometheus/Redis/HistogramTest.php            | 1 -
 13 files changed, 14 deletions(-)

diff --git a/tests/Test/BlackBoxPushGatewayTest.php b/tests/Test/BlackBoxPushGatewayTest.php
index 47469be..6193fc4 100644
--- a/tests/Test/BlackBoxPushGatewayTest.php
+++ b/tests/Test/BlackBoxPushGatewayTest.php
@@ -3,7 +3,6 @@
 
 use GuzzleHttp\Client;
 use PHPUnit\Framework\TestCase;
-use PHPUnit_Framework_TestCase;
 
 use Prometheus\CollectorRegistry;
 use Prometheus\PushGateway;
diff --git a/tests/Test/Prometheus/APC/CollectorRegistryTest.php b/tests/Test/Prometheus/APC/CollectorRegistryTest.php
index 23f7b84..9d73fb7 100644
--- a/tests/Test/Prometheus/APC/CollectorRegistryTest.php
+++ b/tests/Test/Prometheus/APC/CollectorRegistryTest.php
@@ -1,6 +1,5 @@
 <?php
 
-
 namespace Test\Prometheus\APC;
 
 use Prometheus\Storage\APC;
diff --git a/tests/Test/Prometheus/APC/CounterTest.php b/tests/Test/Prometheus/APC/CounterTest.php
index 5ca3b5d..306ec36 100644
--- a/tests/Test/Prometheus/APC/CounterTest.php
+++ b/tests/Test/Prometheus/APC/CounterTest.php
@@ -1,6 +1,5 @@
 <?php
 
-
 namespace Test\Prometheus\APC;
 
 use Prometheus\Storage\APC;
diff --git a/tests/Test/Prometheus/APC/GaugeTest.php b/tests/Test/Prometheus/APC/GaugeTest.php
index f1b2c04..c5dc4f0 100644
--- a/tests/Test/Prometheus/APC/GaugeTest.php
+++ b/tests/Test/Prometheus/APC/GaugeTest.php
@@ -1,6 +1,5 @@
 <?php
 
-
 namespace Test\Prometheus\APC;
 
 use Prometheus\Storage\APC;
diff --git a/tests/Test/Prometheus/APC/HistogramTest.php b/tests/Test/Prometheus/APC/HistogramTest.php
index 19d41eb..2462b25 100644
--- a/tests/Test/Prometheus/APC/HistogramTest.php
+++ b/tests/Test/Prometheus/APC/HistogramTest.php
@@ -1,6 +1,5 @@
 <?php
 
-
 namespace Test\Prometheus\APC;
 
 use Prometheus\Storage\APC;
diff --git a/tests/Test/Prometheus/InMemory/CollectorRegistryTest.php b/tests/Test/Prometheus/InMemory/CollectorRegistryTest.php
index 7309708..5e6b9c7 100644
--- a/tests/Test/Prometheus/InMemory/CollectorRegistryTest.php
+++ b/tests/Test/Prometheus/InMemory/CollectorRegistryTest.php
@@ -1,6 +1,5 @@
 <?php
 
-
 namespace Test\Prometheus\InMemory;
 
 use Prometheus\Storage\InMemory;
diff --git a/tests/Test/Prometheus/InMemory/CounterTest.php b/tests/Test/Prometheus/InMemory/CounterTest.php
index 03ed614..b2176d8 100644
--- a/tests/Test/Prometheus/InMemory/CounterTest.php
+++ b/tests/Test/Prometheus/InMemory/CounterTest.php
@@ -1,6 +1,5 @@
 <?php
 
-
 namespace Test\Prometheus\InMemory;
 
 use Prometheus\Storage\InMemory;
diff --git a/tests/Test/Prometheus/InMemory/GaugeTest.php b/tests/Test/Prometheus/InMemory/GaugeTest.php
index 75e0f3c..84210b6 100644
--- a/tests/Test/Prometheus/InMemory/GaugeTest.php
+++ b/tests/Test/Prometheus/InMemory/GaugeTest.php
@@ -1,6 +1,5 @@
 <?php
 
-
 namespace Test\Prometheus\InMemory;
 
 use Prometheus\Storage\InMemory;
diff --git a/tests/Test/Prometheus/InMemory/HistogramTest.php b/tests/Test/Prometheus/InMemory/HistogramTest.php
index 283ec3e..6569bea 100644
--- a/tests/Test/Prometheus/InMemory/HistogramTest.php
+++ b/tests/Test/Prometheus/InMemory/HistogramTest.php
@@ -1,6 +1,5 @@
 <?php
 
-
 namespace Test\Prometheus\InMemory;
 
 use Prometheus\Storage\InMemory;
diff --git a/tests/Test/Prometheus/Redis/CollectorRegistryTest.php b/tests/Test/Prometheus/Redis/CollectorRegistryTest.php
index b023e23..fbf53b9 100644
--- a/tests/Test/Prometheus/Redis/CollectorRegistryTest.php
+++ b/tests/Test/Prometheus/Redis/CollectorRegistryTest.php
@@ -1,9 +1,7 @@
 <?php
 
-
 namespace Test\Prometheus\Redis;
 
-use function class_exists;
 use Prometheus\Storage\Redis;
 use Test\Prometheus\AbstractCollectorRegistryTest;
 
diff --git a/tests/Test/Prometheus/Redis/CounterTest.php b/tests/Test/Prometheus/Redis/CounterTest.php
index 2a59a7f..4aea278 100644
--- a/tests/Test/Prometheus/Redis/CounterTest.php
+++ b/tests/Test/Prometheus/Redis/CounterTest.php
@@ -1,6 +1,5 @@
 <?php
 
-
 namespace Test\Prometheus\Redis;
 
 use Prometheus\Storage\Redis;
diff --git a/tests/Test/Prometheus/Redis/GaugeTest.php b/tests/Test/Prometheus/Redis/GaugeTest.php
index f5f363a..6ffd300 100644
--- a/tests/Test/Prometheus/Redis/GaugeTest.php
+++ b/tests/Test/Prometheus/Redis/GaugeTest.php
@@ -1,6 +1,5 @@
 <?php
 
-
 namespace Test\Prometheus\Redis;
 
 use Prometheus\Storage\Redis;
diff --git a/tests/Test/Prometheus/Redis/HistogramTest.php b/tests/Test/Prometheus/Redis/HistogramTest.php
index 806a348..40fd314 100644
--- a/tests/Test/Prometheus/Redis/HistogramTest.php
+++ b/tests/Test/Prometheus/Redis/HistogramTest.php
@@ -1,6 +1,5 @@
 <?php
 
-
 namespace Test\Prometheus\Redis;
 
 use Prometheus\Storage\Redis;

From 7f8c5d476a6c7d83a8517fa836d7b21ee824582a Mon Sep 17 00:00:00 2001
From: Daniel <noeldavies@cybershade.org>
Date: Wed, 11 Sep 2019 13:19:27 +0100
Subject: [PATCH 12/28] Bump version in composer and add contribution
 information

---
 composer.json | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/composer.json b/composer.json
index 47aeab2..0800574 100644
--- a/composer.json
+++ b/composer.json
@@ -1,5 +1,6 @@
 {
-    "name": "jimdo/prometheus_client_php",
+    "name": "endclothing/prometheus_client_php",
+    "version": "1.0.0",
     "authors": [
         {
             "name": "Joscha",
@@ -8,6 +9,10 @@
         {
             "name": "Jan Brauer",
             "email": "jan.brauer@jimdo.com"
+        },
+        {
+            "name": "Daniel Noel-Davies",
+            "email": "Daniel.Noel-Davies@endclothing.com"
         }
     ],
     "require": {

From d56d5c42b29754db97256d5eebb163b525eaeae2 Mon Sep 17 00:00:00 2001
From: Daniel <noeldavies@cybershade.org>
Date: Thu, 3 Oct 2019 17:16:19 +0100
Subject: [PATCH 13/28] Add exponential bucket static helper for easy
 generation of histogram buckets

---
 composer.json                                 |  8 -----
 src/Prometheus/Histogram.php                  | 30 ++++++++++++++++++
 .../Test/Prometheus/AbstractHistogramTest.php | 31 +++++++++++++++++++
 3 files changed, 61 insertions(+), 8 deletions(-)

diff --git a/composer.json b/composer.json
index 0800574..fd50694 100644
--- a/composer.json
+++ b/composer.json
@@ -2,14 +2,6 @@
     "name": "endclothing/prometheus_client_php",
     "version": "1.0.0",
     "authors": [
-        {
-            "name": "Joscha",
-            "email": "joscha@schnipseljagd.org"
-        },
-        {
-            "name": "Jan Brauer",
-            "email": "jan.brauer@jimdo.com"
-        },
         {
             "name": "Daniel Noel-Davies",
             "email": "Daniel.Noel-Davies@endclothing.com"
diff --git a/src/Prometheus/Histogram.php b/src/Prometheus/Histogram.php
index f36cf0f..0c20e6c 100644
--- a/src/Prometheus/Histogram.php
+++ b/src/Prometheus/Histogram.php
@@ -62,6 +62,36 @@ public static function getDefaultBuckets(): array
         ];
     }
 
+    /**
+     * @param float $start
+     * @param float $growthFactor
+     * @param int $numberOfBuckets
+     * @return array
+     */
+    public static function exponentialBuckets(float $start, float $growthFactor, int $numberOfBuckets): array
+    {
+        if ($numberOfBuckets < 1) {
+            throw new \InvalidArgumentException('Number of buckets must be a positive integer');
+        }
+
+        if ($start <= 0) {
+            throw new \InvalidArgumentException('The starting position of a set of buckets must be a positive integer');
+        }
+
+        if ($growthFactor <= 1) {
+            throw new \InvalidArgumentException('The growth factor must greater than 1');
+        }
+
+        $buckets = [];
+
+        for ($i = 0; $i < $numberOfBuckets; $i++) {
+            $buckets[$i] = $start;
+            $start *= $growthFactor;
+        }
+
+        return $buckets;
+    }
+
     /**
      * @param double $value e.g. 123
      * @param array $labels e.g. ['status', 'opcode']
diff --git a/tests/Test/Prometheus/AbstractHistogramTest.php b/tests/Test/Prometheus/AbstractHistogramTest.php
index c64d2d8..f170e70 100644
--- a/tests/Test/Prometheus/AbstractHistogramTest.php
+++ b/tests/Test/Prometheus/AbstractHistogramTest.php
@@ -455,6 +455,37 @@ public function isShouldAcceptAnySequenceOfBasicLatinCharactersForLabelValues($v
         }
     }
 
+    /**
+     * @test
+     */
+    public function itShouldBeAbleToGenerateExponentialBucketsGivenSpecificBounds()
+    {
+        $start = 0.05;
+        $growthFactor = 1.5;
+        $numberOfbuckets = 14;
+
+        $generatedBuckets = Histogram::exponentialBuckets($start, $growthFactor, $numberOfbuckets);
+
+        $expectedBuckets = [
+            0.05,
+            0.075,
+            0.1125,
+            0.16875,
+            0.253125,
+            0.3796875,
+            0.56953125,
+            0.854296875,
+            1.2814453125,
+            1.92216796875,
+            2.883251953125,
+            4.3248779296875,
+            6.4873168945313,
+            9.7309753417969,
+        ];
+
+        self::assertEquals($generatedBuckets, $expectedBuckets);
+    }
+
     /**
      * @return array
      * @see isShouldAcceptArbitraryLabelValues

From bc86c725a6a7c86b7fee67ffd6c3f539199661d1 Mon Sep 17 00:00:00 2001
From: Daniel <noeldavies@cybershade.org>
Date: Thu, 3 Oct 2019 18:06:09 +0100
Subject: [PATCH 14/28] Added exponential bucket generation explaination for
 histograms into the readme.

---
 README.md | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/README.md b/README.md
index 03e9e75..6731fe1 100644
--- a/README.md
+++ b/README.md
@@ -83,6 +83,20 @@ $renderer = new RenderTextFormat();
 $result = $renderer->render($registry->getMetricFamilySamples());
 ```
 
+### Advanced Usage
+
+#### Advanced Histogram Usage
+On passing an empty array for the bucket parameter on instantiation, a set of default buckets will be used instead.
+Whilst this is a good base for a typical web application, there is named constructor to assist in the generation of
+exponential / geometric buckets.
+
+Eg:
+```
+Histogram::exponentialBuckets(0.05, 1.5, 10);
+``` 
+
+This will start your buckets with a value of 1.5, grow them by a factor of 1.5 per bucket across a set of 10 buckets. 
+
 Also look at the [examples](examples).
 
 ## Development

From ae9284f6921f7c591b3a76bea2bb17ec92b3f3aa Mon Sep 17 00:00:00 2001
From: Daniel <noeldavies@cybershade.org>
Date: Fri, 4 Oct 2019 10:32:23 +0100
Subject: [PATCH 15/28] Clean up import statements in histogram

---
 src/Prometheus/Histogram.php | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/Prometheus/Histogram.php b/src/Prometheus/Histogram.php
index 0c20e6c..18b8706 100644
--- a/src/Prometheus/Histogram.php
+++ b/src/Prometheus/Histogram.php
@@ -1,5 +1,5 @@
 <?php
-declare(strict_types = 1);
+declare(strict_types=1);
 
 namespace Prometheus;
 
@@ -71,15 +71,15 @@ public static function getDefaultBuckets(): array
     public static function exponentialBuckets(float $start, float $growthFactor, int $numberOfBuckets): array
     {
         if ($numberOfBuckets < 1) {
-            throw new \InvalidArgumentException('Number of buckets must be a positive integer');
+            throw new InvalidArgumentException('Number of buckets must be a positive integer');
         }
 
         if ($start <= 0) {
-            throw new \InvalidArgumentException('The starting position of a set of buckets must be a positive integer');
+            throw new InvalidArgumentException('The starting position of a set of buckets must be a positive integer');
         }
 
         if ($growthFactor <= 1) {
-            throw new \InvalidArgumentException('The growth factor must greater than 1');
+            throw new InvalidArgumentException('The growth factor must greater than 1');
         }
 
         $buckets = [];

From 765fc23389c64794c4e9a5191246a4012f873ecd Mon Sep 17 00:00:00 2001
From: Daniel <noeldavies@cybershade.org>
Date: Fri, 4 Oct 2019 11:45:27 +0100
Subject: [PATCH 16/28] bump version to 1.0.1

---
 composer.json | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/composer.json b/composer.json
index fd50694..305b6bd 100644
--- a/composer.json
+++ b/composer.json
@@ -1,6 +1,6 @@
 {
     "name": "endclothing/prometheus_client_php",
-    "version": "1.0.0",
+    "version": "1.0.1",
     "authors": [
         {
             "name": "Daniel Noel-Davies",

From 25d00760175e580e242d2bc305114bfcc3c98db0 Mon Sep 17 00:00:00 2001
From: Daniel <noeldavies@cybershade.org>
Date: Fri, 4 Oct 2019 12:16:04 +0100
Subject: [PATCH 17/28] Update php required version

---
 composer.json | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/composer.json b/composer.json
index 305b6bd..16e8341 100644
--- a/composer.json
+++ b/composer.json
@@ -8,7 +8,7 @@
         }
     ],
     "require": {
-        "php": "^7.1",
+        "php": "^7.3",
         "ext-json": "*",
         "guzzlehttp/guzzle": "^6.2",
         "symfony/polyfill-apcu": "^1.6"

From b55c01b0dad5088fb66433878315683848e4f1d6 Mon Sep 17 00:00:00 2001
From: Dawid 'DeyV' Polak <Dawid@mentax.pl>
Date: Wed, 23 Oct 2019 08:00:52 +0200
Subject: [PATCH 18/28] Update README.md

^7.3 is required version of php
---
 README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 6731fe1..497bdad 100644
--- a/README.md
+++ b/README.md
@@ -103,7 +103,7 @@ Also look at the [examples](examples).
 
 ### Dependencies
 
-* PHP 7.1
+* PHP ^7.3
 * PHP Redis extension
 * PHP APCu extension
 * [Composer](https://getcomposer.org/doc/00-intro.md#installation-linux-unix-osx)

From fdd6a3dc816119a68b9849cb9ebdb364a05e27af Mon Sep 17 00:00:00 2001
From: Dawid 'DeyV' Polak <Dawid@mentax.pl>
Date: Wed, 23 Oct 2019 08:06:03 +0200
Subject: [PATCH 19/28] Update .travis.yml

Run tests for PHP 7.3 and 7.4, no more support for < 7.3 (required in composer)
---
 .travis.yml | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/.travis.yml b/.travis.yml
index 720eacf..cd51f3b 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,8 +1,7 @@
 language: php
-php:
-  - 5.6
-  - 7.0
-  - 7.1
+php: 
+  - 7.3
+  - 7.4
 
 services:
   - redis-server

From de702c629f4b42166ebe59bf6d506bd153f1030b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C5=A0imon=20Podlipsk=C3=BD?= <simon@podlipsky.net>
Date: Tue, 5 Nov 2019 14:14:36 +0100
Subject: [PATCH 20/28] Add Installation instructions

---
 README.md | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/README.md b/README.md
index 497bdad..260b5d8 100644
--- a/README.md
+++ b/README.md
@@ -12,6 +12,14 @@ You can pick from three adapters.
 Redis, APC or an in memory adapter.
 While the first needs a separate binary running, the second just needs the [APC](https://pecl.php.net/package/APCU) extension to be installed. If you don't need persistent metrics between requests (e.g. a long running cron job or script) the in memory adapter might be suitable to use.
 
+## Installation
+
+Add as [Composer](https://getcomposer.org/) dependency:
+
+```sh
+composer require endclothing/prometheus_client_php
+```
+
 ## Usage
 
 A simple counter:

From c0ea8a389d783f779e15b412ece432cd53742e10 Mon Sep 17 00:00:00 2001
From: Florian Levis <me@levisflorian.name>
Date: Tue, 5 Nov 2019 10:31:56 +0100
Subject: [PATCH 21/28] fix(composer): add replace rule

Add original package (`jimdo/prometheus_client_php`) to the replace list
---
 composer.json | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/composer.json b/composer.json
index 16e8341..09c1442 100644
--- a/composer.json
+++ b/composer.json
@@ -7,6 +7,9 @@
             "email": "Daniel.Noel-Davies@endclothing.com"
         }
     ],
+    "replace: {
+        "jimdo/prometheus_client_php": "*"
+    },
     "require": {
         "php": "^7.3",
         "ext-json": "*",

From 5930a030b142f9eac3c8eaf94d296d2d68617ad7 Mon Sep 17 00:00:00 2001
From: Martins Sipenko <martins.sipenko@gmail.com>
Date: Thu, 7 Nov 2019 13:26:23 +0200
Subject: [PATCH 22/28] Fix invalid json (typo)

---
 composer.json | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/composer.json b/composer.json
index 09c1442..fcfb614 100644
--- a/composer.json
+++ b/composer.json
@@ -7,7 +7,7 @@
             "email": "Daniel.Noel-Davies@endclothing.com"
         }
     ],
-    "replace: {
+    "replace": {
         "jimdo/prometheus_client_php": "*"
     },
     "require": {

From 63966cdd9402a08a22e184038420b358b14e1dbe Mon Sep 17 00:00:00 2001
From: Martins Sipenko <martins.sipenko@gmail.com>
Date: Tue, 19 Nov 2019 20:11:48 +0200
Subject: [PATCH 23/28] Introduce Continuous Integration (#20)

* WIP CI
* Move few things around in CI pipeline
* remove unneeded CI job
---
 .circleci/config.yml            | 81 +++++++++++++++++++++++++++++++++
 .gitattributes                  | 12 +++++
 .travis.yml                     | 19 --------
 composer.json                   | 14 +++++-
 phpunit.xml => phpunit.xml.dist | 23 ++++++----
 5 files changed, 118 insertions(+), 31 deletions(-)
 create mode 100644 .circleci/config.yml
 create mode 100644 .gitattributes
 delete mode 100644 .travis.yml
 rename phpunit.xml => phpunit.xml.dist (51%)

diff --git a/.circleci/config.yml b/.circleci/config.yml
new file mode 100644
index 0000000..471eb48
--- /dev/null
+++ b/.circleci/config.yml
@@ -0,0 +1,81 @@
+unit-config: &unit-config
+  environment:
+    COMPOSER_PREFER_LOWEST: 0
+  steps:
+    - checkout
+
+    - run:
+        name: Install latest composer
+        command: |
+          php -r "copy('https://raw.githubusercontent.com/composer/getcomposer.org/master/web/installer', 'composer-setup.php');"
+          php composer-setup.php
+          php -r "unlink('composer-setup.php');"
+          mv composer.phar /usr/local/bin/composer
+
+    - run:
+        name: Write COMPOSER_PREFER_LOWEST to file
+        command: echo "$COMPOSER_PREFER_LOWEST" > ~/COMPOSER_PREFER_LOWEST.txt
+
+    # Download and cache dependencies
+    - restore_cache:
+        keys:
+        - v1-composer-cache-{{ checksum "~/COMPOSER_PREFER_LOWEST.txt" }}-{{ checksum "composer.json" }}
+        # Fall back to using the latest cache if no exact match is found.
+        - v1-composer-cache-{{ checksum "~/COMPOSER_PREFER_LOWEST.txt" }}
+
+    - run:
+        name: Validate composer files
+        command: composer validate --strict
+
+    - run:
+        name: Install PHP extensions
+        command: |
+            printf '\n' | sudo pecl install redis
+            sudo docker-php-ext-enable redis
+
+    - run:
+        name: Install composer packages
+        command: |
+          if [ $COMPOSER_PREFER_LOWEST -eq "1" ]; then
+            composer update --no-ansi --no-progress --optimize-autoloader --no-interaction --no-plugins --no-scripts --prefer-dist --prefer-stable --prefer-lowest
+          else
+            composer update --no-ansi --no-progress --optimize-autoloader --no-interaction --no-plugins --no-scripts --prefer-dist --prefer-stable
+          fi
+
+    - save_cache:
+        key: v1-composer-cache-{{ checksum "~/COMPOSER_PREFER_LOWEST.txt" }}-{{ checksum "composer.json" }}
+        paths:
+          - ./vendor
+
+    - run:
+        name: Wait for backing services to start
+        command: dockerize -wait tcp://127.0.0.1:6379 -timeout 30s
+
+    - run:
+        name: Run tests
+        command: ./vendor/bin/phpunit
+
+version: 2.1
+jobs:
+  php73:
+    <<: *unit-config
+    docker:
+      - image: circleci/php:7.3-cli-node
+      - image: circleci/redis:5-alpine
+    environment:
+      COMPOSER_PREFER_LOWEST: 0
+
+  php73-lowest:
+    <<: *unit-config
+    docker:
+      - image: circleci/php:7.3-cli-node
+      - image: circleci/redis:5-alpine
+    environment:
+      COMPOSER_PREFER_LOWEST: 1
+
+workflows:
+  version: 2
+  units:
+    jobs:
+      - php73
+      - php73-lowest
diff --git a/.gitattributes b/.gitattributes
new file mode 100644
index 0000000..1044039
--- /dev/null
+++ b/.gitattributes
@@ -0,0 +1,12 @@
+* text=auto
+/.circleci/         export-ignore
+/.github/           export-ignore
+/examples/          export-ignore
+/nginx/             export-ignore
+/php-fpm/           export-ignore
+/tests/             export-ignore
+.gitattributes      export-ignore
+.gitignore          export-ignore
+docker-compose.yml  export-ignore
+phpcs.xml.dist      export-ignore
+phpunit.xml.dist    export-ignore
diff --git a/.travis.yml b/.travis.yml
deleted file mode 100644
index cd51f3b..0000000
--- a/.travis.yml
+++ /dev/null
@@ -1,19 +0,0 @@
-language: php
-php: 
-  - 7.3
-  - 7.4
-
-services:
-  - redis-server
-
-before_script:
-  - echo "apc.enabled = 1" >> ~/.phpenv/versions/$(phpenv version-name)/etc/php.ini
-  - echo "apc.enable_cli = 1" >> ~/.phpenv/versions/$(phpenv version-name)/etc/php.ini
-  - echo "extension = apcu.so" >> ~/.phpenv/versions/$(phpenv version-name)/etc/php.ini
-  - echo "extension = redis.so" >> ~/.phpenv/versions/$(phpenv version-name)/etc/php.ini
-  - composer self-update
-  - composer install --no-interaction --prefer-source --dev
-  - phpenv rehash
-
-script:
-  - vendor/bin/phpunit --verbose --colors
diff --git a/composer.json b/composer.json
index fcfb614..c985b44 100644
--- a/composer.json
+++ b/composer.json
@@ -1,6 +1,8 @@
 {
     "name": "endclothing/prometheus_client_php",
-    "version": "1.0.1",
+    "description": "Prometheus instrumentation library for PHP applications.",
+    "type": "library",
+    "license": "Apache-2.0",
     "authors": [
         {
             "name": "Daniel Noel-Davies",
@@ -33,5 +35,13 @@
             "Test\\Prometheus\\": "tests/"
         }
     },
-    "license": "Apache-2.0"
+    "extra": {
+        "branch-alias": {
+            "dev-master": "1.0-dev"
+        }
+    },
+    "config": {
+        "sort-packages": true
+    },
+    "prefer-stable": true
 }
diff --git a/phpunit.xml b/phpunit.xml.dist
similarity index 51%
rename from phpunit.xml
rename to phpunit.xml.dist
index ab027cb..9fc8a72 100644
--- a/phpunit.xml
+++ b/phpunit.xml.dist
@@ -7,15 +7,18 @@
          convertNoticesToExceptions="true"
          convertWarningsToExceptions="true"
          processIsolation="false"
+         stopOnError="false"
          stopOnFailure="false">
-<testsuites>
-    <testsuite name="Unit">
-        <directory>./tests/Test/Prometheus</directory>
-    </testsuite>
-</testsuites>
-<filter>
-    <whitelist processUncoveredFilesFromWhitelist="true">
-        <directory suffix=".php">./src/Prometheus</directory>
-    </whitelist>
-</filter>
+
+    <testsuites>
+        <testsuite name="Unit">
+            <directory>./tests/Test/Prometheus</directory>
+        </testsuite>
+    </testsuites>
+
+    <filter>
+        <whitelist processUncoveredFilesFromWhitelist="true">
+            <directory suffix=".php">./src/Prometheus</directory>
+        </whitelist>
+    </filter>
 </phpunit>

From 4668eebd7858b3475a6ecbf53266e37c2eee78fd Mon Sep 17 00:00:00 2001
From: kswzr <31246037+kswzr@users.noreply.github.com>
Date: Tue, 19 Nov 2019 19:13:26 +0100
Subject: [PATCH 24/28] Add support for prometheus/pushgateway:>=0.10 (#17)

* allow status 202 in case of downwards compatibility
* add allowance of status 200 for prometheus/pushgateway >=0.10.0
* fix grouping key, because of not matching declerations
* simplify if to add more status code easier
---
 src/Prometheus/PushGateway.php            | 25 ++++---
 tests/Test/Prometheus/PushGatewayTest.php | 79 +++++++++++++++++++++++
 2 files changed, 96 insertions(+), 8 deletions(-)
 create mode 100644 tests/Test/Prometheus/PushGatewayTest.php

diff --git a/src/Prometheus/PushGateway.php b/src/Prometheus/PushGateway.php
index 24b6401..9f8dcd8 100644
--- a/src/Prometheus/PushGateway.php
+++ b/src/Prometheus/PushGateway.php
@@ -4,6 +4,7 @@
 namespace Prometheus;
 
 use GuzzleHttp\Client;
+use GuzzleHttp\ClientInterface;
 use GuzzleHttp\Exception\GuzzleException;
 use RuntimeException;
 
@@ -14,13 +15,20 @@ class PushGateway
      */
     private $address;
 
+    /**
+     * @var ClientInterface
+     */
+    private $client;
+
     /**
      * PushGateway constructor.
-     * @param $address string host:port of the push gateway
+     * @param string $address host:port of the push gateway
+     * @param ClientInterface $client
      */
-    public function __construct($address)
+    public function __construct($address, ClientInterface $client = null)
     {
         $this->address = $address;
+        $this->client = $client ?? new Client();
     }
 
     /**
@@ -31,7 +39,7 @@ public function __construct($address)
      * @param array $groupingKey
      * @throws GuzzleException
      */
-    public function push(CollectorRegistry $collectorRegistry, string $job, array $groupingKey = null): void
+    public function push(CollectorRegistry $collectorRegistry, string $job, array $groupingKey = []): void
     {
         $this->doRequest($collectorRegistry, $job, $groupingKey, 'put');
     }
@@ -44,7 +52,7 @@ public function push(CollectorRegistry $collectorRegistry, string $job, array $g
      * @param $groupingKey
      * @throws GuzzleException
      */
-    public function pushAdd(CollectorRegistry $collectorRegistry, string $job, array $groupingKey = null): void
+    public function pushAdd(CollectorRegistry $collectorRegistry, string $job, array $groupingKey = []): void
     {
         $this->doRequest($collectorRegistry, $job, $groupingKey, 'post');
     }
@@ -56,7 +64,7 @@ public function pushAdd(CollectorRegistry $collectorRegistry, string $job, array
      * @param array $groupingKey
      * @throws GuzzleException
      */
-    public function delete(string $job, array $groupingKey = null): void
+    public function delete(string $job, array $groupingKey = []): void
     {
         $this->doRequest(null, $job, $groupingKey, 'delete');
     }
@@ -76,7 +84,7 @@ private function doRequest(CollectorRegistry $collectorRegistry, string $job, ar
                 $url .= "/" . $label . "/" . $value;
             }
         }
-        $client = new Client();
+
         $requestOptions = [
             'headers' => [
                 'Content-Type' => RenderTextFormat::MIME_TYPE,
@@ -84,13 +92,14 @@ private function doRequest(CollectorRegistry $collectorRegistry, string $job, ar
             'connect_timeout' => 10,
             'timeout' => 20,
         ];
+
         if ($method != 'delete') {
             $renderer = new RenderTextFormat();
             $requestOptions['body'] = $renderer->render($collectorRegistry->getMetricFamilySamples());
         }
-        $response = $client->request($method, $url, $requestOptions);
+        $response = $this->client->request($method, $url, $requestOptions);
         $statusCode = $response->getStatusCode();
-        if ($statusCode != 202) {
+        if (!in_array($statusCode, [200, 202])) {
             $msg = "Unexpected status code "
                 . $statusCode
                 . " received from push gateway "
diff --git a/tests/Test/Prometheus/PushGatewayTest.php b/tests/Test/Prometheus/PushGatewayTest.php
new file mode 100644
index 0000000..d100944
--- /dev/null
+++ b/tests/Test/Prometheus/PushGatewayTest.php
@@ -0,0 +1,79 @@
+<?php
+
+namespace Test\Prometheus;
+
+use GuzzleHttp\Client;
+use GuzzleHttp\Handler\MockHandler;
+use GuzzleHttp\HandlerStack;
+use GuzzleHttp\Psr7\Response;
+use PHPUnit\Framework\TestCase;
+use Prometheus\CollectorRegistry;
+use Prometheus\MetricFamilySamples;
+use Prometheus\PushGateway;
+
+class PushGatewayTest extends TestCase
+{
+    /**
+     * @test
+     *
+     * @doesNotPerformAssertions
+     */
+    public function validResponseShouldNotThrowException(): void
+    {
+        $mockedCollectorRegistry = $this->createMock(CollectorRegistry::class);
+        $mockedCollectorRegistry->method('getMetricFamilySamples')->with()->willReturn([
+            $this->createMock(MetricFamilySamples::class)
+        ]);
+
+        $mockHandler = new MockHandler([
+            new Response(200),
+            new Response(202),
+        ]);
+        $handler = HandlerStack::create($mockHandler);
+        $client = new Client(['handler' => $handler]);
+
+        $pushGateway = new PushGateway('http://foo.bar', $client);
+        $pushGateway->push($mockedCollectorRegistry, 'foo');
+    }
+
+    /**
+     * @test
+     *
+     * @doesNotPerformAnyAssertions
+     */
+    public function invalidResponseShouldThrowRuntimeException(): void
+    {
+        $this->expectException(\RuntimeException::class);
+
+        $mockedCollectorRegistry = $this->createMock(CollectorRegistry::class);
+        $mockedCollectorRegistry->method('getMetricFamilySamples')->with()->willReturn([
+            $this->createMock(MetricFamilySamples::class)
+        ]);
+
+        $mockHandler = new MockHandler([
+            new Response(201),
+            new Response(300),
+        ]);
+        $handler = HandlerStack::create($mockHandler);
+        $client = new Client(['handler' => $handler]);
+
+        $pushGateway = new PushGateway('http://foo.bar', $client);
+        $pushGateway->push($mockedCollectorRegistry, 'foo');
+    }
+
+    /**
+     * @test
+     */
+    public function clientGetsDefinedIfNotSpecified(): void
+    {
+        $this->expectException(\RuntimeException::class);
+
+        $mockedCollectorRegistry = $this->createMock(CollectorRegistry::class);
+        $mockedCollectorRegistry->method('getMetricFamilySamples')->with()->willReturn([
+            $this->createMock(MetricFamilySamples::class)
+        ]);
+
+        $pushGateway = new PushGateway('http://foo.bar');
+        $pushGateway->push($mockedCollectorRegistry, 'foo');
+    }
+}
\ No newline at end of file

From f4c614c1fdb8ca8088595db7d400e5901e056d5f Mon Sep 17 00:00:00 2001
From: Martins Sipenko <martins.sipenko@gmail.com>
Date: Fri, 29 Nov 2019 13:30:44 +0200
Subject: [PATCH 25/28] Add code style check into CI pipeline (#21)

Added CI using CircleCI
---
 .circleci/config.yml                                 |  4 ++++
 composer.json                                        |  5 +++--
 examples/flush_adapter.php                           |  2 +-
 examples/pushgateway.php                             |  2 +-
 examples/some_gauge.php                              |  2 +-
 examples/some_histogram.php                          |  2 +-
 phpcs.xml.dist                                       | 12 ++++++++++++
 src/Prometheus/Collector.php                         |  3 ++-
 src/Prometheus/CollectorRegistry.php                 |  1 +
 src/Prometheus/Counter.php                           |  3 ++-
 src/Prometheus/Gauge.php                             |  3 ++-
 src/Prometheus/Histogram.php                         |  1 +
 src/Prometheus/MetricFamilySamples.php               |  3 ++-
 src/Prometheus/PushGateway.php                       |  3 ++-
 src/Prometheus/RenderTextFormat.php                  |  5 +++--
 src/Prometheus/Sample.php                            |  3 ++-
 src/Prometheus/Storage/APC.php                       |  2 +-
 src/Prometheus/Storage/Adapter.php                   |  3 ++-
 src/Prometheus/Storage/InMemory.php                  |  2 +-
 src/Prometheus/Storage/Redis.php                     |  1 +
 tests/Test/BlackBoxPushGatewayTest.php               |  2 +-
 tests/Test/BlackBoxTest.php                          |  1 +
 tests/Test/Prometheus/APC/HistogramTest.php          |  1 -
 .../Prometheus/AbstractCollectorRegistryTest.php     |  4 +---
 tests/Test/Prometheus/AbstractCounterTest.php        |  3 +--
 tests/Test/Prometheus/AbstractGaugeTest.php          |  3 +--
 tests/Test/Prometheus/AbstractHistogramTest.php      |  5 +----
 tests/Test/Prometheus/InMemory/HistogramTest.php     |  1 -
 tests/Test/Prometheus/PushGatewayTest.php            |  2 +-
 tests/Test/Prometheus/Storage/RedisTest.php          |  1 -
 30 files changed, 52 insertions(+), 33 deletions(-)
 create mode 100644 phpcs.xml.dist

diff --git a/.circleci/config.yml b/.circleci/config.yml
index 471eb48..bcde4cf 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -51,6 +51,10 @@ unit-config: &unit-config
         name: Wait for backing services to start
         command: dockerize -wait tcp://127.0.0.1:6379 -timeout 30s
 
+    - run:
+        name: Run PHP Code Sniffer
+        command: ./vendor/bin/phpcs
+
     - run:
         name: Run tests
         command: ./vendor/bin/phpunit
diff --git a/composer.json b/composer.json
index c985b44..83bfcd3 100644
--- a/composer.json
+++ b/composer.json
@@ -15,11 +15,12 @@
     "require": {
         "php": "^7.3",
         "ext-json": "*",
-        "guzzlehttp/guzzle": "^6.2",
+        "guzzlehttp/guzzle": "^6.3",
         "symfony/polyfill-apcu": "^1.6"
     },
     "require-dev": {
-        "phpunit/phpunit": "^7.5"
+        "phpunit/phpunit": "^7.5",
+        "squizlabs/php_codesniffer": "^3.5"
     },
     "suggest": {
         "ext-redis": "Required if using Redis.",
diff --git a/examples/flush_adapter.php b/examples/flush_adapter.php
index 08cd1e0..8e2ca88 100644
--- a/examples/flush_adapter.php
+++ b/examples/flush_adapter.php
@@ -14,4 +14,4 @@
 } elseif ($adapter === 'in-memory') {
     $inMemoryAdapter = new Prometheus\Storage\InMemory();
     $inMemoryAdapter->flushMemory();
-}
\ No newline at end of file
+}
diff --git a/examples/pushgateway.php b/examples/pushgateway.php
index f850f5c..c337fea 100644
--- a/examples/pushgateway.php
+++ b/examples/pushgateway.php
@@ -22,4 +22,4 @@
 $counter->incBy(6, ['blue']);
 
 $pushGateway = new PushGateway('192.168.59.100:9091');
-$pushGateway->push($registry, 'my_job', ['instance'=>'foo']);
+$pushGateway->push($registry, 'my_job', ['instance' => 'foo']);
diff --git a/examples/some_gauge.php b/examples/some_gauge.php
index 255362b..f8202d2 100644
--- a/examples/some_gauge.php
+++ b/examples/some_gauge.php
@@ -6,7 +6,7 @@
 use Prometheus\Storage\Redis;
 
 
-error_log('c='. $_GET['c']);
+error_log('c=' . $_GET['c']);
 
 $adapter = $_GET['adapter'];
 
diff --git a/examples/some_histogram.php b/examples/some_histogram.php
index eaacb8a..aeb5c1d 100644
--- a/examples/some_histogram.php
+++ b/examples/some_histogram.php
@@ -5,7 +5,7 @@
 use Prometheus\CollectorRegistry;
 use Prometheus\Storage\Redis;
 
-error_log('c='. $_GET['c']);
+error_log('c=' . $_GET['c']);
 
 $adapter = $_GET['adapter'];
 
diff --git a/phpcs.xml.dist b/phpcs.xml.dist
new file mode 100644
index 0000000..78ea685
--- /dev/null
+++ b/phpcs.xml.dist
@@ -0,0 +1,12 @@
+<?xml version="1.0"?>
+<ruleset name="PHP_CodeSniffer">
+    <file>src/</file>
+    <file>tests/</file>
+    <file>examples/</file>
+
+    <exclude-pattern type="relative">vendor/*</exclude-pattern>
+
+    <arg value="nps"/>
+
+    <rule ref="PSR12"/>
+</ruleset>
diff --git a/src/Prometheus/Collector.php b/src/Prometheus/Collector.php
index 26e8275..5f0a440 100644
--- a/src/Prometheus/Collector.php
+++ b/src/Prometheus/Collector.php
@@ -1,4 +1,5 @@
 <?php
+
 declare(strict_types=1);
 
 namespace Prometheus;
@@ -57,7 +58,7 @@ public function __construct(Adapter $storageAdapter, $namespace, $name, $help, $
     /**
      * @return string
      */
-    public abstract function getType();
+    abstract public function getType();
 
     /**
      * @return string
diff --git a/src/Prometheus/CollectorRegistry.php b/src/Prometheus/CollectorRegistry.php
index 739e9c4..541e1d8 100644
--- a/src/Prometheus/CollectorRegistry.php
+++ b/src/Prometheus/CollectorRegistry.php
@@ -1,4 +1,5 @@
 <?php
+
 declare(strict_types=1);
 
 namespace Prometheus;
diff --git a/src/Prometheus/Counter.php b/src/Prometheus/Counter.php
index ae8e726..1b095e5 100644
--- a/src/Prometheus/Counter.php
+++ b/src/Prometheus/Counter.php
@@ -1,5 +1,6 @@
 <?php
-declare(strict_types = 1);
+
+declare(strict_types=1);
 
 namespace Prometheus;
 
diff --git a/src/Prometheus/Gauge.php b/src/Prometheus/Gauge.php
index 9339782..72189f7 100644
--- a/src/Prometheus/Gauge.php
+++ b/src/Prometheus/Gauge.php
@@ -1,5 +1,6 @@
 <?php
-declare(strict_types = 1);
+
+declare(strict_types=1);
 
 namespace Prometheus;
 
diff --git a/src/Prometheus/Histogram.php b/src/Prometheus/Histogram.php
index 18b8706..b67c89f 100644
--- a/src/Prometheus/Histogram.php
+++ b/src/Prometheus/Histogram.php
@@ -1,4 +1,5 @@
 <?php
+
 declare(strict_types=1);
 
 namespace Prometheus;
diff --git a/src/Prometheus/MetricFamilySamples.php b/src/Prometheus/MetricFamilySamples.php
index f600540..5e4ae18 100644
--- a/src/Prometheus/MetricFamilySamples.php
+++ b/src/Prometheus/MetricFamilySamples.php
@@ -1,5 +1,6 @@
 <?php
-declare(strict_types = 1);
+
+declare(strict_types=1);
 
 namespace Prometheus;
 
diff --git a/src/Prometheus/PushGateway.php b/src/Prometheus/PushGateway.php
index 9f8dcd8..8b99982 100644
--- a/src/Prometheus/PushGateway.php
+++ b/src/Prometheus/PushGateway.php
@@ -1,5 +1,6 @@
 <?php
-declare(strict_types = 1);
+
+declare(strict_types=1);
 
 namespace Prometheus;
 
diff --git a/src/Prometheus/RenderTextFormat.php b/src/Prometheus/RenderTextFormat.php
index fcd0679..a5b78dc 100644
--- a/src/Prometheus/RenderTextFormat.php
+++ b/src/Prometheus/RenderTextFormat.php
@@ -1,5 +1,6 @@
 <?php
-declare(strict_types = 1);
+
+declare(strict_types=1);
 
 namespace Prometheus;
 
@@ -13,7 +14,7 @@ class RenderTextFormat
      */
     public function render(array $metrics): string
     {
-        usort( $metrics, function (MetricFamilySamples $a, MetricFamilySamples $b) {
+        usort($metrics, function (MetricFamilySamples $a, MetricFamilySamples $b) {
             return strcmp($a->getName(), $b->getName());
         });
 
diff --git a/src/Prometheus/Sample.php b/src/Prometheus/Sample.php
index 3ed624b..c8774e8 100644
--- a/src/Prometheus/Sample.php
+++ b/src/Prometheus/Sample.php
@@ -1,5 +1,6 @@
 <?php
-declare(strict_types = 1);
+
+declare(strict_types=1);
 
 namespace Prometheus;
 
diff --git a/src/Prometheus/Storage/APC.php b/src/Prometheus/Storage/APC.php
index 397eb39..2fe659d 100644
--- a/src/Prometheus/Storage/APC.php
+++ b/src/Prometheus/Storage/APC.php
@@ -1,4 +1,5 @@
 <?php
+
 declare(strict_types=1);
 
 namespace Prometheus\Storage;
@@ -284,7 +285,6 @@ private function collectHistograms(): array
                     'labelValues' => $decodedLabelValues,
                     'value' => $this->fromInteger($histogramBuckets[$labelValues]['sum']),
                 ];
-
             }
             $histograms[] = new MetricFamilySamples($data);
         }
diff --git a/src/Prometheus/Storage/Adapter.php b/src/Prometheus/Storage/Adapter.php
index 03f258e..068e1d9 100644
--- a/src/Prometheus/Storage/Adapter.php
+++ b/src/Prometheus/Storage/Adapter.php
@@ -1,5 +1,6 @@
 <?php
-declare(strict_types = 1);
+
+declare(strict_types=1);
 
 namespace Prometheus\Storage;
 
diff --git a/src/Prometheus/Storage/InMemory.php b/src/Prometheus/Storage/InMemory.php
index 35c48e1..bfd4c70 100644
--- a/src/Prometheus/Storage/InMemory.php
+++ b/src/Prometheus/Storage/InMemory.php
@@ -1,4 +1,5 @@
 <?php
+
 declare(strict_types=1);
 
 namespace Prometheus\Storage;
@@ -100,7 +101,6 @@ private function collectHistograms(): array
                     'labelValues' => $decodedLabelValues,
                     'value' => $histogramBuckets[$labelValues]['sum'],
                 ];
-
             }
             $histograms[] = new MetricFamilySamples($data);
         }
diff --git a/src/Prometheus/Storage/Redis.php b/src/Prometheus/Storage/Redis.php
index 45f4566..c81316b 100644
--- a/src/Prometheus/Storage/Redis.php
+++ b/src/Prometheus/Storage/Redis.php
@@ -1,4 +1,5 @@
 <?php
+
 declare(strict_types=1);
 
 namespace Prometheus\Storage;
diff --git a/tests/Test/BlackBoxPushGatewayTest.php b/tests/Test/BlackBoxPushGatewayTest.php
index 6193fc4..b3ad8ac 100644
--- a/tests/Test/BlackBoxPushGatewayTest.php
+++ b/tests/Test/BlackBoxPushGatewayTest.php
@@ -1,9 +1,9 @@
 <?php
+
 namespace Test;
 
 use GuzzleHttp\Client;
 use PHPUnit\Framework\TestCase;
-
 use Prometheus\CollectorRegistry;
 use Prometheus\PushGateway;
 use Prometheus\Storage\APC;
diff --git a/tests/Test/BlackBoxTest.php b/tests/Test/BlackBoxTest.php
index f3a2dc0..b4d8a9e 100644
--- a/tests/Test/BlackBoxTest.php
+++ b/tests/Test/BlackBoxTest.php
@@ -1,4 +1,5 @@
 <?php
+
 namespace Test;
 
 use GuzzleHttp\Client;
diff --git a/tests/Test/Prometheus/APC/HistogramTest.php b/tests/Test/Prometheus/APC/HistogramTest.php
index 2462b25..7ef2bed 100644
--- a/tests/Test/Prometheus/APC/HistogramTest.php
+++ b/tests/Test/Prometheus/APC/HistogramTest.php
@@ -17,4 +17,3 @@ public function configureAdapter()
         $this->adapter->flushAPC();
     }
 }
-
diff --git a/tests/Test/Prometheus/AbstractCollectorRegistryTest.php b/tests/Test/Prometheus/AbstractCollectorRegistryTest.php
index 82d9b64..4138026 100644
--- a/tests/Test/Prometheus/AbstractCollectorRegistryTest.php
+++ b/tests/Test/Prometheus/AbstractCollectorRegistryTest.php
@@ -1,9 +1,7 @@
 <?php
 
-
 namespace Test\Prometheus;
 
-
 use PHPUnit\Framework\TestCase;
 use Prometheus\CollectorRegistry;
 use Prometheus\Histogram;
@@ -317,5 +315,5 @@ public function itShouldNotRegisterAHistogramTwice()
     }
 
 
-    public abstract function configureAdapter();
+    abstract public function configureAdapter();
 }
diff --git a/tests/Test/Prometheus/AbstractCounterTest.php b/tests/Test/Prometheus/AbstractCounterTest.php
index d96b71e..c60295a 100644
--- a/tests/Test/Prometheus/AbstractCounterTest.php
+++ b/tests/Test/Prometheus/AbstractCounterTest.php
@@ -1,6 +1,5 @@
 <?php
 
-
 namespace Test\Prometheus;
 
 use InvalidArgumentException;
@@ -25,7 +24,7 @@ public function setUp()
         $this->configureAdapter();
     }
 
-    public abstract function configureAdapter();
+    abstract public function configureAdapter();
 
     /**
      * @test
diff --git a/tests/Test/Prometheus/AbstractGaugeTest.php b/tests/Test/Prometheus/AbstractGaugeTest.php
index 4536f48..a744a97 100644
--- a/tests/Test/Prometheus/AbstractGaugeTest.php
+++ b/tests/Test/Prometheus/AbstractGaugeTest.php
@@ -1,6 +1,5 @@
 <?php
 
-
 namespace Test\Prometheus;
 
 use InvalidArgumentException;
@@ -25,7 +24,7 @@ public function setUp()
         $this->configureAdapter();
     }
 
-    public abstract function configureAdapter();
+    abstract public function configureAdapter();
 
     /**
      * @test
diff --git a/tests/Test/Prometheus/AbstractHistogramTest.php b/tests/Test/Prometheus/AbstractHistogramTest.php
index f170e70..9e7b348 100644
--- a/tests/Test/Prometheus/AbstractHistogramTest.php
+++ b/tests/Test/Prometheus/AbstractHistogramTest.php
@@ -1,6 +1,5 @@
 <?php
 
-
 namespace Test\Prometheus;
 
 use InvalidArgumentException;
@@ -10,7 +9,6 @@
 use Prometheus\Sample;
 use Prometheus\Storage\Adapter;
 
-
 /**
  * See https://prometheus.io/docs/instrumenting/exposition_formats/
  */
@@ -26,7 +24,7 @@ public function setUp()
         $this->configureAdapter();
     }
 
-    public abstract function configureAdapter();
+    abstract public function configureAdapter();
 
     /**
      * @test
@@ -250,7 +248,6 @@ public function itShouldProvideDefaultBuckets()
             'some_metric',
             'this is for testing',
             []
-
         );
         $histogram->observe(0.11);
         $histogram->observe(0.03);
diff --git a/tests/Test/Prometheus/InMemory/HistogramTest.php b/tests/Test/Prometheus/InMemory/HistogramTest.php
index 6569bea..50d402d 100644
--- a/tests/Test/Prometheus/InMemory/HistogramTest.php
+++ b/tests/Test/Prometheus/InMemory/HistogramTest.php
@@ -17,4 +17,3 @@ public function configureAdapter()
         $this->adapter->flushMemory();
     }
 }
-
diff --git a/tests/Test/Prometheus/PushGatewayTest.php b/tests/Test/Prometheus/PushGatewayTest.php
index d100944..e04dbf1 100644
--- a/tests/Test/Prometheus/PushGatewayTest.php
+++ b/tests/Test/Prometheus/PushGatewayTest.php
@@ -76,4 +76,4 @@ public function clientGetsDefinedIfNotSpecified(): void
         $pushGateway = new PushGateway('http://foo.bar');
         $pushGateway->push($mockedCollectorRegistry, 'foo');
     }
-}
\ No newline at end of file
+}
diff --git a/tests/Test/Prometheus/Storage/RedisTest.php b/tests/Test/Prometheus/Storage/RedisTest.php
index 9ba0c65..ce4dfbc 100644
--- a/tests/Test/Prometheus/Storage/RedisTest.php
+++ b/tests/Test/Prometheus/Storage/RedisTest.php
@@ -21,5 +21,4 @@ public function itShouldThrowAnExceptionOnConnectionFailure()
         $redis->collect();
         $redis->flushRedis();
     }
-
 }

From ce813f7caefb139c8ec2a4fb1a1c422a6e80571d Mon Sep 17 00:00:00 2001
From: Martins Sipenko <martins.sipenko@gmail.com>
Date: Fri, 29 Nov 2019 13:35:57 +0200
Subject: [PATCH 26/28] Inject Redis via named constructor (#8)

* Inject Redis via named constructor

* change method name

* Added withExistingConnection test

* Fix for redis prefix support and respective tests

* removed unneeded code

* phpcbf
---
 src/Prometheus/Storage/Redis.php              | 75 ++++++++++++-------
 tests/Test/Prometheus/AbstractCounterTest.php | 18 ++---
 .../Redis/CounterWithPrefixTest.php           | 24 ++++++
 .../Prometheus/Redis/GaugeWithPrefixTest.php  | 24 ++++++
 .../Redis/HistogramWithPrefixTest.php         | 24 ++++++
 tests/Test/Prometheus/Storage/RedisTest.php   | 19 ++++-
 6 files changed, 147 insertions(+), 37 deletions(-)
 create mode 100644 tests/Test/Prometheus/Redis/CounterWithPrefixTest.php
 create mode 100644 tests/Test/Prometheus/Redis/GaugeWithPrefixTest.php
 create mode 100644 tests/Test/Prometheus/Redis/HistogramWithPrefixTest.php

diff --git a/src/Prometheus/Storage/Redis.php b/src/Prometheus/Storage/Redis.php
index c81316b..85e3000 100644
--- a/src/Prometheus/Storage/Redis.php
+++ b/src/Prometheus/Storage/Redis.php
@@ -42,6 +42,11 @@ class Redis implements Adapter
      */
     private $redis;
 
+    /**
+     * @var boolean
+     */
+    private $connectionInitialized = false;
+
     /**
      * Redis constructor.
      * @param array $options
@@ -52,6 +57,19 @@ public function __construct(array $options = [])
         $this->redis = new \Redis();
     }
 
+    public static function fromExistingConnection(\Redis $redis): self
+    {
+        if ($redis->isConnected() === false) {
+            throw new StorageException('Connection to Redis server not established');
+        }
+
+        $self = new self();
+        $self->connectionInitialized = true;
+        $self->redis = $redis;
+
+        return $self;
+    }
+
     /**
      * @param array $options
      */
@@ -100,6 +118,10 @@ function (array $metric) {
      */
     private function openConnection(): void
     {
+        if ($this->connectionInitialized === true) {
+            return;
+        }
+
         $connectionStatus = $this->connectToServer();
         if ($connectionStatus === false) {
             throw new StorageException("Can't connect to Redis server", 0);
@@ -153,25 +175,26 @@ public function updateHistogram(array $data): void
         $metaData = $data;
         unset($metaData['value']);
         unset($metaData['labelValues']);
+
         $this->redis->eval(
             <<<LUA
-local increment = redis.call('hIncrByFloat', KEYS[1], KEYS[2], ARGV[1])
-redis.call('hIncrBy', KEYS[1], KEYS[3], 1)
-if increment == ARGV[1] then
-    redis.call('hSet', KEYS[1], '__meta', ARGV[2])
-    redis.call('sAdd', KEYS[4], KEYS[1])
+local increment = redis.call('hIncrByFloat', KEYS[1], ARGV[1], ARGV[3])
+redis.call('hIncrBy', KEYS[1], ARGV[2], 1)
+if increment == ARGV[3] then
+    redis.call('hSet', KEYS[1], '__meta', ARGV[4])
+    redis.call('sAdd', KEYS[2], KEYS[1])
 end
 LUA
             ,
             [
                 $this->toMetricKey($data),
+                self::$prefix . Histogram::TYPE . self::PROMETHEUS_METRIC_KEYS_SUFFIX,
                 json_encode(['b' => 'sum', 'labelValues' => $data['labelValues']]),
                 json_encode(['b' => $bucketToIncrease, 'labelValues' => $data['labelValues']]),
-                self::$prefix . Histogram::TYPE . self::PROMETHEUS_METRIC_KEYS_SUFFIX,
                 $data['value'],
                 json_encode($metaData),
             ],
-            4
+            2
         );
     }
 
@@ -188,30 +211,30 @@ public function updateGauge(array $data): void
         unset($metaData['command']);
         $this->redis->eval(
             <<<LUA
-local result = redis.call(KEYS[2], KEYS[1], KEYS[4], ARGV[1])
+local result = redis.call(ARGV[1], KEYS[1], ARGV[2], ARGV[3])
 
-if KEYS[2] == 'hSet' then
+if ARGV[1] == 'hSet' then
     if result == 1 then
-        redis.call('hSet', KEYS[1], '__meta', ARGV[2])
-        redis.call('sAdd', KEYS[3], KEYS[1])
+        redis.call('hSet', KEYS[1], '__meta', ARGV[4])
+        redis.call('sAdd', KEYS[2], KEYS[1])
     end
 else
-    if result == ARGV[1] then
-        redis.call('hSet', KEYS[1], '__meta', ARGV[2])
-        redis.call('sAdd', KEYS[3], KEYS[1])
+    if result == ARGV[3] then
+        redis.call('hSet', KEYS[1], '__meta', ARGV[4])
+        redis.call('sAdd', KEYS[2], KEYS[1])
     end
 end
 LUA
             ,
             [
                 $this->toMetricKey($data),
-                $this->getRedisCommand($data['command']),
                 self::$prefix . Gauge::TYPE . self::PROMETHEUS_METRIC_KEYS_SUFFIX,
+                $this->getRedisCommand($data['command']),
                 json_encode($data['labelValues']),
                 $data['value'],
                 json_encode($metaData),
             ],
-            4
+            2
         );
     }
 
@@ -228,23 +251,23 @@ public function updateCounter(array $data): void
         unset($metaData['command']);
         $this->redis->eval(
             <<<LUA
-local result = redis.call(KEYS[2], KEYS[1], KEYS[4], ARGV[1])
-if result == tonumber(ARGV[1]) then
-    redis.call('hMSet', KEYS[1], '__meta', ARGV[2])
-    redis.call('sAdd', KEYS[3], KEYS[1])
+local result = redis.call(ARGV[1], KEYS[1], ARGV[3], ARGV[2])
+if result == tonumber(ARGV[2]) then
+    redis.call('hMSet', KEYS[1], '__meta', ARGV[4])
+    redis.call('sAdd', KEYS[2], KEYS[1])
 end
 return result
 LUA
             ,
             [
                 $this->toMetricKey($data),
-                $this->getRedisCommand($data['command']),
                 self::$prefix . Counter::TYPE . self::PROMETHEUS_METRIC_KEYS_SUFFIX,
-                json_encode($data['labelValues']),
+                $this->getRedisCommand($data['command']),
                 $data['value'],
+                json_encode($data['labelValues']),
                 json_encode($metaData),
             ],
-            4
+            2
         );
     }
 
@@ -257,7 +280,7 @@ private function collectHistograms(): array
         sort($keys);
         $histograms = [];
         foreach ($keys as $key) {
-            $raw = $this->redis->hGetAll($key);
+            $raw = $this->redis->hGetAll(str_replace($this->redis->_prefix(''), '', $key));
             $histogram = json_decode($raw['__meta'], true);
             unset($raw['__meta']);
             $histogram['samples'] = [];
@@ -334,7 +357,7 @@ private function collectGauges(): array
         sort($keys);
         $gauges = [];
         foreach ($keys as $key) {
-            $raw = $this->redis->hGetAll($key);
+            $raw = $this->redis->hGetAll(str_replace($this->redis->_prefix(''), '', $key));
             $gauge = json_decode($raw['__meta'], true);
             unset($raw['__meta']);
             $gauge['samples'] = [];
@@ -363,7 +386,7 @@ private function collectCounters(): array
         sort($keys);
         $counters = [];
         foreach ($keys as $key) {
-            $raw = $this->redis->hGetAll($key);
+            $raw = $this->redis->hGetAll(str_replace($this->redis->_prefix(''), '', $key));
             $counter = json_decode($raw['__meta'], true);
             unset($raw['__meta']);
             $counter['samples'] = [];
diff --git a/tests/Test/Prometheus/AbstractCounterTest.php b/tests/Test/Prometheus/AbstractCounterTest.php
index c60295a..03caa22 100644
--- a/tests/Test/Prometheus/AbstractCounterTest.php
+++ b/tests/Test/Prometheus/AbstractCounterTest.php
@@ -31,10 +31,10 @@ abstract public function configureAdapter();
      */
     public function itShouldIncreaseWithLabels()
     {
-        $gauge = new Counter($this->adapter, 'test', 'some_metric', 'this is for testing', ['foo', 'bar']);
-        $gauge->inc(['lalal', 'lululu']);
-        $gauge->inc(['lalal', 'lululu']);
-        $gauge->inc(['lalal', 'lululu']);
+        $counter = new Counter($this->adapter, 'test', 'some_metric', 'this is for testing', ['foo', 'bar']);
+        $counter->inc(['lalal', 'lululu']);
+        $counter->inc(['lalal', 'lululu']);
+        $counter->inc(['lalal', 'lululu']);
         $this->assertThat(
             $this->adapter->collect(),
             $this->equalTo(
@@ -65,8 +65,8 @@ public function itShouldIncreaseWithLabels()
      */
     public function itShouldIncreaseWithoutLabelWhenNoLabelsAreDefined()
     {
-        $gauge = new Counter($this->adapter, 'test', 'some_metric', 'this is for testing');
-        $gauge->inc();
+        $counter = new Counter($this->adapter, 'test', 'some_metric', 'this is for testing');
+        $counter->inc();
         $this->assertThat(
             $this->adapter->collect(),
             $this->equalTo(
@@ -97,9 +97,9 @@ public function itShouldIncreaseWithoutLabelWhenNoLabelsAreDefined()
      */
     public function itShouldIncreaseTheCounterByAnArbitraryInteger()
     {
-        $gauge = new Counter($this->adapter, 'test', 'some_metric', 'this is for testing', ['foo', 'bar']);
-        $gauge->inc(['lalal', 'lululu']);
-        $gauge->incBy(123, ['lalal', 'lululu']);
+        $counter = new Counter($this->adapter, 'test', 'some_metric', 'this is for testing', ['foo', 'bar']);
+        $counter->inc(['lalal', 'lululu']);
+        $counter->incBy(123, ['lalal', 'lululu']);
         $this->assertThat(
             $this->adapter->collect(),
             $this->equalTo(
diff --git a/tests/Test/Prometheus/Redis/CounterWithPrefixTest.php b/tests/Test/Prometheus/Redis/CounterWithPrefixTest.php
new file mode 100644
index 0000000..0409140
--- /dev/null
+++ b/tests/Test/Prometheus/Redis/CounterWithPrefixTest.php
@@ -0,0 +1,24 @@
+<?php
+
+namespace Test\Prometheus\Redis;
+
+use Prometheus\Storage\Redis;
+use Test\Prometheus\AbstractCounterTest;
+
+/**
+ * See https://prometheus.io/docs/instrumenting/exposition_formats/
+ * @requires extension redis
+ */
+class CounterWithPrefixTest extends AbstractCounterTest
+{
+    public function configureAdapter()
+    {
+        $connection = new \Redis();
+        $connection->connect(REDIS_HOST);
+
+        $connection->setOption(\Redis::OPT_PREFIX, 'prefix:');
+
+        $this->adapter = Redis::fromExistingConnection($connection);
+        $this->adapter->flushRedis();
+    }
+}
diff --git a/tests/Test/Prometheus/Redis/GaugeWithPrefixTest.php b/tests/Test/Prometheus/Redis/GaugeWithPrefixTest.php
new file mode 100644
index 0000000..1ba4d0e
--- /dev/null
+++ b/tests/Test/Prometheus/Redis/GaugeWithPrefixTest.php
@@ -0,0 +1,24 @@
+<?php
+
+namespace Test\Prometheus\Redis;
+
+use Prometheus\Storage\Redis;
+use Test\Prometheus\AbstractGaugeTest;
+
+/**
+ * See https://prometheus.io/docs/instrumenting/exposition_formats/
+ * @requires extension redis
+ */
+class GaugeWithPrefixTest extends AbstractGaugeTest
+{
+    public function configureAdapter()
+    {
+        $connection = new \Redis();
+        $connection->connect(REDIS_HOST);
+
+        $connection->setOption(\Redis::OPT_PREFIX, 'prefix:');
+
+        $this->adapter = Redis::fromExistingConnection($connection);
+        $this->adapter->flushRedis();
+    }
+}
diff --git a/tests/Test/Prometheus/Redis/HistogramWithPrefixTest.php b/tests/Test/Prometheus/Redis/HistogramWithPrefixTest.php
new file mode 100644
index 0000000..4c25388
--- /dev/null
+++ b/tests/Test/Prometheus/Redis/HistogramWithPrefixTest.php
@@ -0,0 +1,24 @@
+<?php
+
+namespace Test\Prometheus\Redis;
+
+use Prometheus\Storage\Redis;
+use Test\Prometheus\AbstractHistogramTest;
+
+/**
+ * See https://prometheus.io/docs/instrumenting/exposition_formats/
+ * @requires extension redis
+ */
+class HistogramWithPrefixTest extends AbstractHistogramTest
+{
+    public function configureAdapter()
+    {
+        $connection = new \Redis();
+        $connection->connect(REDIS_HOST);
+
+        $connection->setOption(\Redis::OPT_PREFIX, 'prefix:');
+
+        $this->adapter = Redis::fromExistingConnection($connection);
+        $this->adapter->flushRedis();
+    }
+}
diff --git a/tests/Test/Prometheus/Storage/RedisTest.php b/tests/Test/Prometheus/Storage/RedisTest.php
index ce4dfbc..9f2df78 100644
--- a/tests/Test/Prometheus/Storage/RedisTest.php
+++ b/tests/Test/Prometheus/Storage/RedisTest.php
@@ -12,13 +12,28 @@ class RedisTest extends TestCase
 {
     /**
      * @test
-     * @expectedException Prometheus\Exception\StorageException
-     * @expectedExceptionMessage Can't connect to Redis server
      */
     public function itShouldThrowAnExceptionOnConnectionFailure()
     {
         $redis = new Redis(['host' => '/dev/null']);
+
+        $this->expectException(StorageException::class);
+        $this->expectExceptionMessage("Can't connect to Redis server");
+
         $redis->collect();
         $redis->flushRedis();
     }
+
+    /**
+     * @test
+     */
+    public function itShouldThrowExceptionWhenInjectedRedisIsNotConnected()
+    {
+        $connection = new \Redis();
+
+        $this->expectException(StorageException::class);
+        $this->expectExceptionMessage('Connection to Redis server not established');
+
+        Redis::fromExistingConnection($connection);
+    }
 }

From 44cccb41d77540f561c909b54e8752f31aee6735 Mon Sep 17 00:00:00 2001
From: Martins Sipenko <martins.sipenko@gmail.com>
Date: Fri, 29 Nov 2019 14:21:57 +0200
Subject: [PATCH 27/28] Update phpunit to version 8 (#23)

* Update phpunit to version 8

* fix shield

* Require PHPUnit version at least 8.4
---
 .gitignore                                    |  3 +-
 README.md                                     |  6 ++--
 composer.json                                 |  2 +-
 .../AbstractCollectorRegistryTest.php         | 25 +++++++++-----
 tests/Test/Prometheus/AbstractCounterTest.php | 16 ++++-----
 tests/Test/Prometheus/AbstractGaugeTest.php   | 16 ++++-----
 .../Test/Prometheus/AbstractHistogramTest.php | 34 +++++++++----------
 7 files changed, 56 insertions(+), 46 deletions(-)

diff --git a/.gitignore b/.gitignore
index 44ab7a5..fc951dd 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,4 +2,5 @@
 *.iml
 /.idea/
 composer.lock
-composer.phar
\ No newline at end of file
+composer.phar
+.phpunit.result.cache
diff --git a/README.md b/README.md
index 260b5d8..35e4f1f 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,6 @@
 # A prometheus client library written in PHP
 
-[![Build Status](https://travis-ci.org/Jimdo/prometheus_client_php.svg?branch=master)](https://travis-ci.org/Jimdo/prometheus_client_php)
+[![CircleCI](https://circleci.com/gh/endclothing/prometheus_client_php/tree/master.svg?style=shield)](https://circleci.com/gh/endclothing/prometheus_client_php/tree/master)
 
 This library uses Redis or APCu to do the client side aggregation.
 If using Redis, we recommend to run a local Redis instance next to your PHP workers.
@@ -101,9 +101,9 @@ exponential / geometric buckets.
 Eg:
 ```
 Histogram::exponentialBuckets(0.05, 1.5, 10);
-``` 
+```
 
-This will start your buckets with a value of 1.5, grow them by a factor of 1.5 per bucket across a set of 10 buckets. 
+This will start your buckets with a value of 1.5, grow them by a factor of 1.5 per bucket across a set of 10 buckets.
 
 Also look at the [examples](examples).
 
diff --git a/composer.json b/composer.json
index 83bfcd3..e98dcf4 100644
--- a/composer.json
+++ b/composer.json
@@ -19,7 +19,7 @@
         "symfony/polyfill-apcu": "^1.6"
     },
     "require-dev": {
-        "phpunit/phpunit": "^7.5",
+        "phpunit/phpunit": "^8.4",
         "squizlabs/php_codesniffer": "^3.5"
     },
     "suggest": {
diff --git a/tests/Test/Prometheus/AbstractCollectorRegistryTest.php b/tests/Test/Prometheus/AbstractCollectorRegistryTest.php
index 4138026..76f3160 100644
--- a/tests/Test/Prometheus/AbstractCollectorRegistryTest.php
+++ b/tests/Test/Prometheus/AbstractCollectorRegistryTest.php
@@ -8,6 +8,8 @@
 use Prometheus\RenderTextFormat;
 use Prometheus\Storage\Adapter;
 use Prometheus\Storage\Redis;
+use Prometheus\Exception\MetricsRegistrationException;
+use Prometheus\Exception\MetricNotFoundException;
 
 abstract class AbstractCollectorRegistryTest extends TestCase
 {
@@ -21,7 +23,7 @@ abstract class AbstractCollectorRegistryTest extends TestCase
      */
     private $renderer;
 
-    public function setUp()
+    public function setUp(): void
     {
         $this->configureAdapter();
         $this->renderer = new RenderTextFormat();
@@ -204,77 +206,84 @@ public function itShouldIncreaseACounterWithoutNamespace()
 
     /**
      * @test
-     * @expectedException \Prometheus\Exception\MetricsRegistrationException
      */
     public function itShouldForbidRegisteringTheSameCounterTwice()
     {
         $registry = new CollectorRegistry($this->adapter);
         $registry->registerCounter('foo', 'metric', 'help');
+
+        $this->expectException(MetricsRegistrationException::class);
         $registry->registerCounter('foo', 'metric', 'help');
     }
 
     /**
      * @test
-     * @expectedException \Prometheus\Exception\MetricsRegistrationException
      */
     public function itShouldForbidRegisteringTheSameCounterWithDifferentLabels()
     {
         $registry = new CollectorRegistry($this->adapter);
         $registry->registerCounter('foo', 'metric', 'help', ["foo", "bar"]);
+
+        $this->expectException(MetricsRegistrationException::class);
         $registry->registerCounter('foo', 'metric', 'help', ["spam", "eggs"]);
     }
 
     /**
      * @test
-     * @expectedException \Prometheus\Exception\MetricsRegistrationException
      */
     public function itShouldForbidRegisteringTheSameHistogramTwice()
     {
         $registry = new CollectorRegistry($this->adapter);
         $registry->registerHistogram('foo', 'metric', 'help');
+
+        $this->expectException(MetricsRegistrationException::class);
         $registry->registerHistogram('foo', 'metric', 'help');
     }
 
     /**
      * @test
-     * @expectedException \Prometheus\Exception\MetricsRegistrationException
      */
     public function itShouldForbidRegisteringTheSameHistogramWithDifferentLabels()
     {
         $registry = new CollectorRegistry($this->adapter);
         $registry->registerCounter('foo', 'metric', 'help', ["foo", "bar"]);
+
+        $this->expectException(MetricsRegistrationException::class);
         $registry->registerCounter('foo', 'metric', 'help', ["spam", "eggs"]);
     }
 
     /**
      * @test
-     * @expectedException \Prometheus\Exception\MetricsRegistrationException
      */
     public function itShouldForbidRegisteringTheSameGaugeTwice()
     {
         $registry = new CollectorRegistry($this->adapter);
         $registry->registerGauge('foo', 'metric', 'help');
+
+        $this->expectException(MetricsRegistrationException::class);
         $registry->registerGauge('foo', 'metric', 'help');
     }
 
     /**
      * @test
-     * @expectedException \Prometheus\Exception\MetricsRegistrationException
      */
     public function itShouldForbidRegisteringTheSameGaugeWithDifferentLabels()
     {
         $registry = new CollectorRegistry($this->adapter);
         $registry->registerGauge('foo', 'metric', 'help', ["foo", "bar"]);
+
+        $this->expectException(MetricsRegistrationException::class);
         $registry->registerGauge('foo', 'metric', 'help', ["spam", "eggs"]);
     }
 
     /**
      * @test
-     * @expectedException \Prometheus\Exception\MetricNotFoundException
      */
     public function itShouldThrowAnExceptionWhenGettingANonExistentMetric()
     {
         $registry = new CollectorRegistry($this->adapter);
+
+        $this->expectException(MetricNotFoundException::class);
         $registry->getGauge("not_here", "go_away");
     }
 
diff --git a/tests/Test/Prometheus/AbstractCounterTest.php b/tests/Test/Prometheus/AbstractCounterTest.php
index 03caa22..a932939 100644
--- a/tests/Test/Prometheus/AbstractCounterTest.php
+++ b/tests/Test/Prometheus/AbstractCounterTest.php
@@ -19,7 +19,7 @@ abstract class AbstractCounterTest extends TestCase
      */
     public $adapter;
 
-    public function setUp()
+    public function setUp(): void
     {
         $this->configureAdapter();
     }
@@ -127,19 +127,19 @@ public function itShouldIncreaseTheCounterByAnArbitraryInteger()
 
     /**
      * @test
-     * @expectedException InvalidArgumentException
      */
     public function itShouldRejectInvalidMetricsNames()
     {
+        $this->expectException(InvalidArgumentException::class);
         new Counter($this->adapter, 'test', 'some metric invalid metric', 'help');
     }
 
     /**
      * @test
-     * @expectedException InvalidArgumentException
      */
     public function itShouldRejectInvalidLabelNames()
     {
+        $this->expectException(InvalidArgumentException::class);
         new Counter($this->adapter, 'test', 'some_metric', 'help', ['invalid label']);
     }
 
@@ -156,20 +156,20 @@ public function isShouldAcceptAnySequenceOfBasicLatinCharactersForLabelValues($v
         $histogram->inc([$value]);
 
         $metrics = $this->adapter->collect();
-        self::assertInternalType('array', $metrics);
-        self::assertCount(1, $metrics);
-        self::assertContainsOnlyInstancesOf(MetricFamilySamples::class, $metrics);
+        $this->assertIsArray($metrics);
+        $this->assertCount(1, $metrics);
+        $this->assertContainsOnlyInstancesOf(MetricFamilySamples::class, $metrics);
 
         $metric = reset($metrics);
         $samples = $metric->getSamples();
-        self::assertContainsOnlyInstancesOf(Sample::class, $samples);
+        $this->assertContainsOnlyInstancesOf(Sample::class, $samples);
 
         foreach ($samples as $sample) {
             $labels = array_combine(
                 array_merge($metric->getLabelNames(), $sample->getLabelNames()),
                 $sample->getLabelValues()
             );
-            self::assertEquals($value, $labels[$label]);
+            $this->assertEquals($value, $labels[$label]);
         }
     }
 
diff --git a/tests/Test/Prometheus/AbstractGaugeTest.php b/tests/Test/Prometheus/AbstractGaugeTest.php
index a744a97..393c087 100644
--- a/tests/Test/Prometheus/AbstractGaugeTest.php
+++ b/tests/Test/Prometheus/AbstractGaugeTest.php
@@ -19,7 +19,7 @@ abstract class AbstractGaugeTest extends TestCase
      */
     public $adapter;
 
-    public function setUp()
+    public function setUp(): void
     {
         $this->configureAdapter();
     }
@@ -295,19 +295,19 @@ public function itShouldOverwriteWhenSettingTwice()
 
     /**
      * @test
-     * @expectedException InvalidArgumentException
      */
     public function itShouldRejectInvalidMetricsNames()
     {
+        $this->expectException(InvalidArgumentException::class);
         new Gauge($this->adapter, 'test', 'some metric invalid metric', 'help');
     }
 
     /**
      * @test
-     * @expectedException InvalidArgumentException
      */
     public function itShouldRejectInvalidLabelNames()
     {
+        $this->expectException(InvalidArgumentException::class);
         new Gauge($this->adapter, 'test', 'some_metric', 'help', ['invalid label']);
     }
 
@@ -324,20 +324,20 @@ public function isShouldAcceptAnySequenceOfBasicLatinCharactersForLabelValues($v
         $histogram->inc([$value]);
 
         $metrics = $this->adapter->collect();
-        self::assertInternalType('array', $metrics);
-        self::assertCount(1, $metrics);
-        self::assertContainsOnlyInstancesOf(MetricFamilySamples::class, $metrics);
+        $this->assertIsArray($metrics);
+        $this->assertCount(1, $metrics);
+        $this->assertContainsOnlyInstancesOf(MetricFamilySamples::class, $metrics);
 
         $metric = reset($metrics);
         $samples = $metric->getSamples();
-        self::assertContainsOnlyInstancesOf(Sample::class, $samples);
+        $this->assertContainsOnlyInstancesOf(Sample::class, $samples);
 
         foreach ($samples as $sample) {
             $labels = array_combine(
                 array_merge($metric->getLabelNames(), $sample->getLabelNames()),
                 $sample->getLabelValues()
             );
-            self::assertEquals($value, $labels[$label]);
+            $this->assertEquals($value, $labels[$label]);
         }
     }
 
diff --git a/tests/Test/Prometheus/AbstractHistogramTest.php b/tests/Test/Prometheus/AbstractHistogramTest.php
index 9e7b348..d5f9ebb 100644
--- a/tests/Test/Prometheus/AbstractHistogramTest.php
+++ b/tests/Test/Prometheus/AbstractHistogramTest.php
@@ -19,7 +19,7 @@ abstract class AbstractHistogramTest extends TestCase
      */
     public $adapter;
 
-    public function setUp()
+    public function setUp(): void
     {
         $this->configureAdapter();
     }
@@ -374,51 +374,51 @@ public function itShouldProvideDefaultBuckets()
 
     /**
      * @test
-     * @expectedException InvalidArgumentException
-     * @expectedExceptionMessage Histogram buckets must be in increasing order
      */
     public function itShouldThrowAnExceptionWhenTheBucketSizesAreNotIncreasing()
     {
+        $this->expectException(InvalidArgumentException::class);
+        $this->expectExceptionMessage('Histogram buckets must be in increasing order');
         new Histogram($this->adapter, 'test', 'some_metric', 'this is for testing', [], [1, 1]);
     }
 
     /**
      * @test
-     * @expectedException InvalidArgumentException
-     * @expectedExceptionMessage Histogram must have at least one bucket
      */
     public function itShouldThrowAnExceptionWhenThereIsLessThanOneBucket()
     {
+        $this->expectException(InvalidArgumentException::class);
+        $this->expectExceptionMessage('Histogram must have at least one bucket');
         new Histogram($this->adapter, 'test', 'some_metric', 'this is for testing', [], []);
     }
 
     /**
      * @test
-     * @expectedException InvalidArgumentException
-     * @expectedExceptionMessage Histogram cannot have a label named
      */
     public function itShouldThrowAnExceptionWhenThereIsALabelNamedLe()
     {
+        $this->expectException(InvalidArgumentException::class);
+        $this->expectExceptionMessage('Histogram cannot have a label named');
         new Histogram($this->adapter, 'test', 'some_metric', 'this is for testing', ['le'], [1]);
     }
 
     /**
      * @test
-     * @expectedException InvalidArgumentException
-     * @expectedExceptionMessage Invalid metric name
      */
     public function itShouldRejectInvalidMetricsNames()
     {
+        $this->expectException(InvalidArgumentException::class);
+        $this->expectExceptionMessage('Invalid metric name');
         new Histogram($this->adapter, 'test', 'some invalid metric', 'help', [], [1]);
     }
 
     /**
      * @test
-     * @expectedException InvalidArgumentException
-     * @expectedExceptionMessage Invalid label name
      */
     public function itShouldRejectInvalidLabelNames()
     {
+        $this->expectException(InvalidArgumentException::class);
+        $this->expectExceptionMessage('Invalid label name');
         new Histogram($this->adapter, 'test', 'some_metric', 'help', ['invalid label'], [1]);
     }
 
@@ -435,20 +435,20 @@ public function isShouldAcceptAnySequenceOfBasicLatinCharactersForLabelValues($v
         $histogram->observe(1, [$value]);
 
         $metrics = $this->adapter->collect();
-        self::assertInternalType('array', $metrics);
-        self::assertCount(1, $metrics);
-        self::assertContainsOnlyInstancesOf(MetricFamilySamples::class, $metrics);
+        $this->assertIsArray($metrics);
+        $this->assertCount(1, $metrics);
+        $this->assertContainsOnlyInstancesOf(MetricFamilySamples::class, $metrics);
 
         $metric = reset($metrics);
         $samples = $metric->getSamples();
-        self::assertContainsOnlyInstancesOf(Sample::class, $samples);
+        $this->assertContainsOnlyInstancesOf(Sample::class, $samples);
 
         foreach ($samples as $sample) {
             $labels = array_combine(
                 array_merge($metric->getLabelNames(), $sample->getLabelNames()),
                 $sample->getLabelValues()
             );
-            self::assertEquals($value, $labels[$label]);
+            $this->assertEquals($value, $labels[$label]);
         }
     }
 
@@ -480,7 +480,7 @@ public function itShouldBeAbleToGenerateExponentialBucketsGivenSpecificBounds()
             9.7309753417969,
         ];
 
-        self::assertEquals($generatedBuckets, $expectedBuckets);
+        $this->assertEquals($generatedBuckets, $expectedBuckets);
     }
 
     /**

From 65662f51094ddfe047f3bdc8cde08d25bd7af494 Mon Sep 17 00:00:00 2001
From: Martins Sipenko <martins.sipenko@gmail.com>
Date: Fri, 29 Nov 2019 14:25:20 +0200
Subject: [PATCH 28/28] Run CI on PHP version 7.4 (#25)

---
 .circleci/config.yml | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/.circleci/config.yml b/.circleci/config.yml
index bcde4cf..2d1525e 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -61,6 +61,22 @@ unit-config: &unit-config
 
 version: 2.1
 jobs:
+  php74:
+    <<: *unit-config
+    docker:
+      - image: circleci/php:7.4-cli-node
+      - image: circleci/redis:5-alpine
+    environment:
+      COMPOSER_PREFER_LOWEST: 0
+
+  php74-lowest:
+    <<: *unit-config
+    docker:
+      - image: circleci/php:7.4-cli-node
+      - image: circleci/redis:5-alpine
+    environment:
+      COMPOSER_PREFER_LOWEST: 1
+
   php73:
     <<: *unit-config
     docker:
@@ -81,5 +97,7 @@ workflows:
   version: 2
   units:
     jobs:
+      - php74
+      - php74-lowest
       - php73
       - php73-lowest