Add an integration test for the composer install

.github/workflows/ci.yaml

@@ -0,0 +1,32 @@
+name: CI
+
+on:
+  push:
+
+jobs:
+
+  integration-test-composer:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: 8.3
+          tools: composer:v2
+
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      # Github doesn't seem to like a working-directory arg for a custom action
+      # and I ideally want to test this works as expected in the root
+      - name: Copy test files to root
+        run:  cp test/cached-composer-install/composer.* .
+
+      - name: Install with dev dependencies
+        uses: ./cached-composer-install
+
+      - name: Check all packages installed
+        env:
+          EXPECT_DEV_PACKAGES: installed
+        run: php test/cached-composer-install/check-installed.php

test/cached-composer-install/check-installed.php

@@ -0,0 +1,32 @@
+<?php
+
+$expect_installed = match (getenv('EXPECT_DEV_PACKAGES')) {
+    'installed' => [
+        'psr/log' => true,
+        'psr/cache' => true,
+    ],
+    'not-installed' => [
+        'psr/log' => true,
+        'psr/cache' => false,
+    ],
+    default => throw new InvalidArgumentException('Define EXPECT_DEV_PACKAGES as installed|not-installed')
+};
+
+require_once './vendor/autoload.php';
+
+$actual = [
+    'psr/log' => interface_exists(\Psr\Log\LoggerInterface::class),
+    'psr/cache' => interface_exists(\Psr\Cache\CacheItemPoolInterface::class),
+];
+
+if ($actual === $expect_installed) {
+    echo "Correct packages were installed: ";
+    print_r($actual);
+    exit;
+}
+
+print "Installed packages: ";
+print_r($actual);
+print "Did not match expected: ";
+print_r($expect_installed);
+exit(1);

test/cached-composer-install/composer.json

@@ -0,0 +1,8 @@
+{
+    "require": {
+        "psr/log": "^3.0"
+    },
+    "require-dev": {
+        "psr/cache": "^3.0"
+    }
+}