Add duration functionality

core/src/main/java/com/tngtech/valueprovider/AbstractValueProvider.java

@@ -609,6 +609,29 @@ public LocalTime localTime() {
         return LocalTime.ofSecondOfDay(longNumber(0, secondsPerDay - 1));
     }
 
+    /**
+     * Generates a {@link Duration} in [0 ; {@code max}].
+     * 
+     * @param max the upper bound of the generated {@link Duration}.
+     * @return the generated {@link Duration}.
+     */
+    public Duration duration(Duration max) {
+        return Duration.ofMillis(longNumber(0, max.toMillis()));
+    } 
+
+    /**
+     * Generates a {@link Duration} in [{@code min} ; {@code max}].
+     * 
+     * @param min the lower bound of the generated {@link Duration}.
+     * @param max the upper bound of the generated {@link Duration}.
+     * @return the generated {@link Duration}.
+     * @throws IllegalArgumentException if {@code min} > {@code max}.
+     */
+    public Duration duration(Duration min, Duration max) {
+        checkArgument(min.compareTo(max) <= 0, "min %s must be less than or equal max %s", min, max);
+        return Duration.ofMillis(longNumber(min.toMillis(), max.toMillis()));
+    }
+
     /**
      * Draws one element from the elements of an Enum class.
      * <p>

core/src/test/java/com/tngtech/valueprovider/ValueProviderTest.java

@@ -7,6 +7,7 @@
 import java.net.InetAddress;
 import java.net.URL;
 import java.net.UnknownHostException;
+import java.time.Duration;
 import java.time.LocalDateTime;
 import java.util.Arrays;
 import java.util.Collection;
@@ -21,6 +22,7 @@
 import java.util.stream.Stream;
 
 import lombok.Data;
+
 import org.junit.jupiter.api.DynamicTest;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.TestFactory;
@@ -95,6 +97,8 @@ private static Collection<MethodInvocation> allMethodInvocations() {
         int min = random.intNumber(100, 1000);
         int max = random.intNumber(1001, 2000);
         int numLines = random.intNumber(2, 10);
+        Duration minDuration = Duration.ofHours(1);
+        Duration maxDuration = Duration.ofDays(1);
 
         return newArrayList(
                 invoke("booleanValue"),
@@ -123,6 +127,8 @@ private static Collection<MethodInvocation> allMethodInvocations() {
                 invoke("fixedLocalDate"),
                 invoke("localDateBetweenYears", min, max),
                 invoke("localTime"),
+                invoke("duration", maxDuration),
+                invoke("duration", minDuration, maxDuration),
                 invoke("fixedLocalDateTime"),
                 invoke("fixedDecoratedStrings", numLines),
                 invoke("fixedDecoratedStrings", numLines, random.randomString(stringLength))
@@ -538,6 +544,21 @@ void numericString_should_reject_too_small_length_wrt_min() {
         assertThat(thrown.getMessage()).contains("" + tooSmallLength, "" + min);
     }
 
+    @Test
+    void duration_should_be_smaller_than_max_duration() {
+        ValueProvider random = withRandomValues();
+        assertThat(random.duration(Duration.ofDays(1)))
+                .isLessThanOrEqualTo(Duration.ofDays(1));
+    }
+
+    @Test
+    void duration_should_be_bigger_than_min_and_smaller_than_max_duration() {
+        ValueProvider random = withRandomValues();
+        assertThat(random.duration(Duration.ofMinutes(1), Duration.ofDays(1)))
+                .isGreaterThanOrEqualTo(Duration.ofMinutes(1))
+                .isLessThanOrEqualTo(Duration.ofDays(1));
+    }
+
     @Test
     void oneOf_should_return_single_value() {
         ValueProvider random = withRandomValues();