🐛 (#47): Ensure tests are reproducible in JUnit5

junit5/src/main/kotlin/fr/xgouchet/elmyr/junit5/ForgeConfiguration.kt

@@ -14,5 +14,6 @@ import org.junit.platform.commons.annotation.Testable
 @MustBeDocumented
 @Inherited
 annotation class ForgeConfiguration(
-    val value: KClass<out ForgeConfigurator>
+    val value: KClass<out ForgeConfigurator>,
+    val seed: Long = 0L
 )

junit5/src/main/kotlin/fr/xgouchet/elmyr/junit5/ForgeExtension.kt

@@ -15,6 +15,7 @@ import fr.xgouchet.elmyr.junit5.params.LongForgeryParamResolver
 import java.lang.reflect.Constructor
 import java.util.Locale
 import org.junit.jupiter.api.extension.BeforeAllCallback
+import org.junit.jupiter.api.extension.BeforeEachCallback
 import org.junit.jupiter.api.extension.BeforeTestExecutionCallback
 import org.junit.jupiter.api.extension.ExtensionContext
 import org.junit.jupiter.api.extension.ParameterContext
@@ -32,6 +33,7 @@ import org.junit.platform.commons.support.AnnotationSupport
  */
 class ForgeExtension :
         BeforeAllCallback,
+        BeforeEachCallback,
         BeforeTestExecutionCallback,
         TestExecutionExceptionHandler,
         ParameterResolver {
@@ -62,17 +64,25 @@ class ForgeExtension :
 
     // endregion
 
-    // region BeforeTestExecutionCallback
+    // region BeforeEachCallback
 
     /** @inheritdoc */
-    override fun beforeTestExecution(context: ExtensionContext) {
+    override fun beforeEach(context: ExtensionContext) {
         resetSeed(context)
         val target = context.requiredTestInstance
         injector.inject(instanceForge, target)
     }
 
     // endregion
 
+    // region BeforeTestExecutionCallback
+
+    /** @inheritdoc */
+    override fun beforeTestExecution(context: ExtensionContext) {
+    }
+
+    // endregion
+
     // region TestExecutionExceptionHandler
 
     /** @inheritdoc */
@@ -131,13 +141,15 @@ class ForgeExtension :
 
     // region Internal
 
-    private fun resetSeed(extensionContext: ExtensionContext) {
-        val seed = (System.nanoTime() and SEED_MASK)
-        instanceForge.seed = seed
+    private fun resetSeed(context: ExtensionContext) {
+        val configurations = getConfigurations(context)
+        val seed = configurations.map { it.seed }
+                .firstOrNull { it != 0L }
+        instanceForge.seed = seed ?: (System.nanoTime() and SEED_MASK)
     }
 
-    private fun getConfigurators(context: ExtensionContext): List<ForgeConfigurator> {
-        val result = mutableListOf<ForgeConfigurator>()
+    private fun getConfigurations(context: ExtensionContext): List<ForgeConfiguration> {
+        val result = mutableListOf<ForgeConfiguration>()
         var currentContext = context
 
         while (currentContext != context.root) {
@@ -148,8 +160,7 @@ class ForgeExtension :
                     )
 
             if (annotation.isPresent) {
-                val configurator = annotation.get().value.java.newInstance()
-                result.add(configurator)
+                result.add(annotation.get())
             }
 
             currentContext = currentContext.parent.get()
@@ -158,6 +169,11 @@ class ForgeExtension :
         return result
     }
 
+    private fun getConfigurators(context: ExtensionContext): List<ForgeConfigurator> {
+        return getConfigurations(context)
+                .map { it.value.java.newInstance() }
+    }
+
     // endregion
 
     companion object {

junit5/src/test/java/fr/xgouchet/elmyr/junit5/JavaReproducibilityTest.java

@@ -0,0 +1,63 @@
+package fr.xgouchet.elmyr.junit5;
+
+import fr.xgouchet.elmyr.Forge;
+import fr.xgouchet.elmyr.annotation.FloatForgery;
+import fr.xgouchet.elmyr.annotation.Forgery;
+import fr.xgouchet.elmyr.annotation.IntForgery;
+import fr.xgouchet.elmyr.junit5.dummy.Bar;
+import fr.xgouchet.elmyr.junit5.dummy.Foo;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+
+@ExtendWith(ForgeExtension.class)
+@ForgeConfiguration(value = JavaAnnotationTest.Configurator.class, seed = JavaReproducibilityTest.SEED)
+public class JavaReproducibilityTest {
+
+    public static final long SEED = 0x85F04771A07L;
+
+    @Forgery
+    private Foo fakeFoo = null;
+
+    @Forgery
+    public Bar fakeBar = null;
+
+    @BeforeEach
+    public void setUp(Forge forge) {
+        checkSeedNotChanged(forge);
+        checkForgeryInjected();
+    }
+
+    @Test
+    public void testRun1() {
+    }
+
+    @Test
+    public void testRun2() {
+    }
+
+    @Test
+    public void testRun3(@Forgery Foo foo, @Forgery Bar bar) {
+        assertThat(foo.getI()).isEqualTo(-1314996441);
+        assertThat(bar.getS()).isEqualTo("xiqcgqfmbjoaevbo");
+    }
+
+    @Test
+    public void testRun4(@FloatForgery float f, @IntForgery int i) {
+        assertThat(f).isEqualTo(3.1084288E38f);
+        assertThat(i).isEqualTo(177874237);
+    }
+
+    private void checkSeedNotChanged(Forge forge) {
+        assertThat(forge.getSeed()).isEqualTo(SEED);
+    }
+
+    private void checkForgeryInjected() {
+        assertThat(fakeFoo.getI()).isEqualTo(-119626925);
+        assertThat(fakeBar.getS()).isEqualTo("ttcji");
+    }
+
+}

junit5/src/test/kotlin/fr/xgouchet/elmyr/junit5/KotlinReproducibilityTest.kt

@@ -0,0 +1,70 @@
+package fr.xgouchet.elmyr.junit5
+
+import fr.xgouchet.elmyr.Forge
+import fr.xgouchet.elmyr.ForgeConfigurator
+import fr.xgouchet.elmyr.annotation.FloatForgery
+import fr.xgouchet.elmyr.annotation.Forgery
+import fr.xgouchet.elmyr.annotation.IntForgery
+import fr.xgouchet.elmyr.junit5.dummy.Bar
+import fr.xgouchet.elmyr.junit5.dummy.BarFactory
+import fr.xgouchet.elmyr.junit5.dummy.Foo
+import fr.xgouchet.elmyr.junit5.dummy.FooFactory
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.api.BeforeEach
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.extension.ExtendWith
+
+@ExtendWith(ForgeExtension::class)
+@ForgeConfiguration(value = KotlinReproducibilityTest.Configurator::class, seed = KotlinReproducibilityTest.SEED)
+class KotlinReproducibilityTest {
+
+    @Forgery
+    private lateinit var fakeFoo: Foo
+    @Forgery
+    private lateinit var fakeBar: Bar
+
+    @BeforeEach
+    fun setUp(forge: Forge) {
+        checkSeedNotChanged(forge)
+        checkForgeryInjected()
+    }
+
+    @Test
+    fun testRun1() {
+    }
+
+    @Test
+    fun testRun2() {
+    }
+
+    @Test
+    fun testRun3(@Forgery foo: Foo, @Forgery bar: Bar) {
+        assertThat(foo.i).isEqualTo(1834174735)
+        assertThat(bar.s).isEqualTo("wfpwhlvm")
+    }
+
+    @Test
+    fun testRun4(@FloatForgery f: Float, @IntForgery i: Int) {
+        assertThat(f).isEqualTo(2.5332062E38f)
+        assertThat(i).isEqualTo(-1217237951)
+    }
+
+    private fun checkSeedNotChanged(forge: Forge) {
+        assertThat(forge.seed).isEqualTo(SEED)
+    }
+
+    private fun checkForgeryInjected() {
+        assertThat(fakeFoo.i).isEqualTo(1596512190)
+        assertThat(fakeBar.s).isEqualTo("grquxsqwqccdwk")
+    }
+
+    class Configurator : ForgeConfigurator {
+        override fun configure(forge: Forge) {
+            forge.addFactory(Foo::class.java, FooFactory())
+            forge.addFactory(Bar::class.java, BarFactory())
+        }
+    }
+    companion object {
+        const val SEED = 0xD774670189EL
+    }
+}