provide name of test class to re-run in failure reproduction info, if…

… test class hierarchy of failed test contains Lifecycle PER_CLASS

Signed-off-by: Jonas Höf <jonas.hoef@tngtech.com>

README.md

@@ -499,7 +499,7 @@ at com.tngtech.valueprovider.ValueProviderRule$1.evaluate(ValueProviderRule.java
 ```
 
 If the failure is related to random data, you can easily reproduce it. Just specify the above shown JVM system
-properties in the command line when you re-run the test, e.g., in your IDE:
+properties in the command line when you re-run the failed test, e.g., in your IDE:
 
 ```
 -Dvalue.provider.factory.test.class.seed=0
@@ -524,8 +524,17 @@ for details). The nesting may be arbitrarily deep, i.e. `@Nested` classes may co
 test lifecycle may be chosen individually for the main test class as well as for each `@Nested` test class. As long as
 the main test class and all `@Nested` test classes use the default test lifecycle `PER_METHOD`, it is again sufficient
 to rerun the individual test method, regardless if it is in the main class or any nested class. As soon as the lifecycle
-`PER_CLASS` is used for one of the classes in the nesting hierarchy where the failure occured, you have to rerun __all
-test methods of this hierarchy__ of test classes to reproduce the failure.
+`PER_CLASS` is used for one or more classes in the nesting hierarchy where the failure occured, you have to re-run __all
+test methods of this hierarchy__ of test classes to reproduce the failure. For convenience, the failure message
+generated by the infrastructure provides the name of the root test class of this hierarchy in addition to the seed
+values as shown in the following example:
+
+```
+"If the failure is related to random ValueProviders, re-run all tests of 'com.tngtech.valueprovider.ValueProviderExceptionTest' and specify the following system properties for the JVM to reproduce:
+-Dvalue.provider.factory.test.class.seed=0
+-Dvalue.provider.factory.test.method.seed=-5385145878463633929
+-Dvalue.provider.factory.reference.date.time=2024-12-09T17:02:50.109"
+```
 
 ### Reproducible ValueProviders
 

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

@@ -1,29 +1,43 @@
 package com.tngtech.valueprovider;
 
-import static com.tngtech.valueprovider.InitializationCreator.VALUE_PROVIDER_FACTORY_REFERENCE_DATE_TIME_PROPERTY;
-import static com.tngtech.valueprovider.InitializationCreator.VALUE_PROVIDER_FACTORY_TEST_CLASS_SEED_PROPERTY;
-import static com.tngtech.valueprovider.InitializationCreator.VALUE_PROVIDER_FACTORY_TEST_METHOD_SEED_PROPERTY;
-import static com.tngtech.valueprovider.ValueProviderFactory.getFormattedReferenceDateTime;
-import static com.tngtech.valueprovider.ValueProviderFactory.getTestClassSeed;
-import static com.tngtech.valueprovider.ValueProviderFactory.getTestMethodSeed;
+import java.util.Optional;
+
+import com.google.common.annotations.VisibleForTesting;
+
+import static com.tngtech.valueprovider.InitializationCreator.*;
+import static com.tngtech.valueprovider.ValueProviderFactory.*;
 import static java.lang.String.format;
+import static java.util.Optional.empty;
 
+@SuppressWarnings("OptionalUsedAsFieldOrParameterType")
 public class ValueProviderException extends RuntimeException {
     ValueProviderException() {
-        super(provideFailureReproductionInfo());
+        this(empty());
+    }
+
+    ValueProviderException(Optional<Class<?>> testClassToReRunForReproduction) {
+        super(provideFailureReproductionInfo(testClassToReRunForReproduction));
     }
 
-    static String provideFailureReproductionInfo() {
+    @VisibleForTesting
+    static String provideFailureReproductionInfo(Optional<Class<?>> testClassToReRunForReproduction) {
         long testClassSeed = getTestClassSeed();
         long testMethodSeed = getTestMethodSeed();
         String referenceDateTime = getFormattedReferenceDateTime();
         return format(
-                "If the failure is related to random ValueProviders, specify the following system properties for the JVM to reproduce:%n" +
+                "If the failure is related to random ValueProviders, %sspecify the following system properties for the JVM to reproduce:%n" +
                         "-D%s=%d%n" +
                         "-D%s=%d%n" +
                         "-D%s=%s",
+                formatReRunMessageFor(testClassToReRunForReproduction),
                 VALUE_PROVIDER_FACTORY_TEST_CLASS_SEED_PROPERTY, testClassSeed,
                 VALUE_PROVIDER_FACTORY_TEST_METHOD_SEED_PROPERTY, testMethodSeed,
                 VALUE_PROVIDER_FACTORY_REFERENCE_DATE_TIME_PROPERTY, referenceDateTime);
     }
+
+    private static String formatReRunMessageFor(Optional<Class<?>> testClassToReRunForReproduction) {
+        return testClassToReRunForReproduction.map(testClass ->
+                        format("re-run all tests of '%s' and ", testClass.getName()))
+                .orElse("");
+    }
 }

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

@@ -1,13 +1,11 @@
 package com.tngtech.valueprovider;
 
+import java.util.Optional;
+
 import org.junit.jupiter.api.Test;
 
-import static com.tngtech.valueprovider.InitializationCreator.VALUE_PROVIDER_FACTORY_REFERENCE_DATE_TIME_PROPERTY;
-import static com.tngtech.valueprovider.InitializationCreator.VALUE_PROVIDER_FACTORY_TEST_CLASS_SEED_PROPERTY;
-import static com.tngtech.valueprovider.InitializationCreator.VALUE_PROVIDER_FACTORY_TEST_METHOD_SEED_PROPERTY;
-import static com.tngtech.valueprovider.ValueProviderFactory.getFormattedReferenceDateTime;
-import static com.tngtech.valueprovider.ValueProviderFactory.getTestClassSeed;
-import static com.tngtech.valueprovider.ValueProviderFactory.getTestMethodSeed;
+import static com.tngtech.valueprovider.InitializationCreator.*;
+import static com.tngtech.valueprovider.ValueProviderFactory.*;
 import static org.assertj.core.api.Assertions.assertThat;
 
 class ValueProviderExceptionTest {
@@ -26,4 +24,14 @@ void should_show_seed_values_reference_date_time_and_respective_system_propertie
                         VALUE_PROVIDER_FACTORY_TEST_METHOD_SEED_PROPERTY,
                         VALUE_PROVIDER_FACTORY_REFERENCE_DATE_TIME_PROPERTY);
     }
+
+    @Test
+    void should_show_test_class_to_re_run_for_failure_reproduction_if_provided() {
+        Class<?> testClassToReRun = this.getClass();
+        ValueProviderException exception = new ValueProviderException(Optional.of(testClassToReRun));
+
+        String message = exception.getMessage();
+
+        assertThat(message).contains(testClassToReRun.getName());
+    }
 }

junit5/src/main/java/com/tngtech/valueprovider/ValueProviderExtension.java

@@ -13,6 +13,7 @@
 
 import static com.tngtech.valueprovider.ValueProviderExtension.TestMethodCycleState.*;
 import static java.lang.System.identityHashCode;
+import static java.util.Optional.empty;
 import static org.junit.jupiter.api.TestInstance.Lifecycle.PER_CLASS;
 import static org.junit.jupiter.api.TestInstance.Lifecycle.PER_METHOD;
 
@@ -78,9 +79,13 @@ public void beforeEach(ExtensionContext context) {
     public void handleTestExecutionException(ExtensionContext context, Throwable throwable) throws Throwable {
         logger.debug("{} handleTestExecutionException {}",
                 identityHashCode(this), buildQualifiedTestMethodName(context));
+        // If the test class hierarchy of the failed test method contains any class(es) with Lifecycle PER_CLASS,
+        // all test methods of this hierarchy must be re-run to reproduce the failure.
+        // The root test class of the hierarchy must therefore be shown in the failure reproduction info.
+        Optional<Class<?>> testClassToReRunForReproduction = getRootClassInHierarchyWithLifecyclePerClass(context);
         // Note: handleTestExecutionException() is invoked BEFORE afterEach, i.e. BEFORE seed is reset,
         // so that the correct seed values appear in the failure message
-        throwable.addSuppressed(new ValueProviderException());
+        throwable.addSuppressed(new ValueProviderException(testClassToReRunForReproduction));
         throw throwable;
     }
 
@@ -179,6 +184,24 @@ private static boolean isLastTestClassInHierarchyWithLifecyclePerClass(Extension
         return remainingLifecyclesInHierarchy.isEmpty() || containsOnlyLifecyclePerMethod(remainingLifecyclesInHierarchy);
     }
 
+    private static Optional<Class<?>> getRootClassInHierarchyWithLifecyclePerClass(ExtensionContext startContext) {
+        List<Class<?>> testClassesInHierarchyWithLifecyclePerClass = new ArrayList<>();
+        traverseContextHierarchy(startContext, context ->
+                addTestClassAtBeginningIfLifecyclePerClass(context, testClassesInHierarchyWithLifecyclePerClass));
+        if (testClassesInHierarchyWithLifecyclePerClass.isEmpty()) {
+            return empty();
+        }
+        return Optional.of(testClassesInHierarchyWithLifecyclePerClass.get(0));
+    }
+
+    private static void addTestClassAtBeginningIfLifecyclePerClass(ExtensionContext context, List<Class<?>> addTo) {
+        if (!isLifecycle(context, PER_CLASS)) {
+            return;
+        }
+        context.getTestClass().ifPresent(testClass ->
+                addTo.add(0, testClass));
+    }
+
     private static boolean testClassHierarchyHasOnlyLifecyclePerMethod(ExtensionContext context) {
         Set<Lifecycle> lifecyclesInHierarchy = determineLifecyclesInTestClassHierarchy(Optional.of(context));
         return containsOnlyLifecyclePerMethod(lifecyclesInHierarchy);