Revert "Refine TestInstancePostProcessor API regarding access to test…

… instance"

This reverts commit 1d30b76, reversing
changes made to 3640af5.

documentation/src/docs/asciidoc/release-notes-5.0.0-M5.adoc

@@ -128,10 +128,6 @@ is placed on the Java 9 module path.
 * `TestExecutionCondition` and `ContainerExecutionCondition` have been replaced by a
   single, general purpose extension API for conditional test execution:
   `ExecutionCondition`.
-* The `postProcessTestInstance()` method in the `TestInstancePostProcessor` API is no
-  longer supplied a direct reference to the test instance. However, the test instance
-  can now be retrieved from the supplied `ExtensionContext` via its
-  `Optional<Object> getTestInstance()` method.
 
 [[release-notes-5.0.0-m5-migration-extension-api]]
 .Extension API Migration

documentation/src/test/java/example/TestInfoDemo.java

@@ -24,8 +24,7 @@
 class TestInfoDemo {
 
 	TestInfoDemo(TestInfo testInfo) {
-		String displayName = testInfo.getDisplayName();
-		assertTrue(displayName.equals("TEST 1") || displayName.equals("test2()"));
+		assertEquals("TestInfo Demo", testInfo.getDisplayName());
 	}
 
 	@BeforeEach

junit-jupiter-api/src/main/java/org/junit/jupiter/api/extension/TestInstancePostProcessor.java

@@ -25,18 +25,16 @@
  * <p>Implementations must provide a no-args constructor.
  *
  * @since 5.0
- * @see #postProcessTestInstance(ExtensionContext)
  */
 @API(Experimental)
 public interface TestInstancePostProcessor extends Extension {
 
 	/**
-	 * Callback for post-processing the test instance in the supplied
-	 * {@link ExtensionContext}.
+	 * Callback for post-processing the supplied test instance.
 	 *
+	 * @param testInstance the instance to post-process; never {@code null}
 	 * @param context the current extension context; never {@code null}
-	 * @see ExtensionContext#getTestInstance()
 	 */
-	void postProcessTestInstance(ExtensionContext context) throws Exception;
+	void postProcessTestInstance(Object testInstance, ExtensionContext context) throws Exception;
 
 }

junit-jupiter-engine/src/main/java/org/junit/jupiter/engine/execution/AbstractExtensionContext.java → junit-jupiter-engine/src/main/java/org/junit/jupiter/engine/descriptor/AbstractExtensionContext.java

@@ -8,18 +8,18 @@
  * http://www.eclipse.org/legal/epl-v10.html
  */
 
-package org.junit.jupiter.engine.execution;
+package org.junit.jupiter.engine.descriptor;
 
 import static java.util.stream.Collectors.toCollection;
-import static org.junit.platform.commons.meta.API.Usage.Internal;
 
 import java.util.LinkedHashSet;
 import java.util.Map;
 import java.util.Optional;
 import java.util.Set;
 
 import org.junit.jupiter.api.extension.ExtensionContext;
-import org.junit.platform.commons.meta.API;
+import org.junit.jupiter.engine.execution.ExtensionValuesStore;
+import org.junit.jupiter.engine.execution.NamespaceAwareStore;
 import org.junit.platform.commons.util.Preconditions;
 import org.junit.platform.engine.EngineExecutionListener;
 import org.junit.platform.engine.TestDescriptor;
@@ -29,28 +29,25 @@
 /**
  * @since 5.0
  */
-@API(Internal)
-public abstract class AbstractExtensionContext<T extends TestDescriptor> implements ExtensionContext {
+abstract class AbstractExtensionContext<T extends TestDescriptor> implements ExtensionContext {
 
 	private final ExtensionContext parent;
 	private final EngineExecutionListener engineExecutionListener;
 	private final T testDescriptor;
 	private final ExtensionValuesStore valuesStore;
 
-	private Object testInstance;
-
-	protected AbstractExtensionContext(AbstractExtensionContext<?> parent,
-			EngineExecutionListener engineExecutionListener, T testDescriptor) {
+	AbstractExtensionContext(ExtensionContext parent, EngineExecutionListener engineExecutionListener,
+			T testDescriptor) {
 		this.parent = parent;
 		this.engineExecutionListener = engineExecutionListener;
 		this.testDescriptor = testDescriptor;
 		this.valuesStore = createStore(parent);
 	}
 
-	private ExtensionValuesStore createStore(AbstractExtensionContext<?> parent) {
+	private ExtensionValuesStore createStore(ExtensionContext parent) {
 		ExtensionValuesStore parentStore = null;
 		if (parent != null) {
-			parentStore = parent.valuesStore;
+			parentStore = ((AbstractExtensionContext<?>) parent).valuesStore;
 		}
 		return new ExtensionValuesStore(parentStore);
 	}
@@ -65,15 +62,6 @@ public String getDisplayName() {
 		return getTestDescriptor().getDisplayName();
 	}
 
-	public void setTestInstance(Object testInstance) {
-		this.testInstance = testInstance;
-	}
-
-	@Override
-	public Optional<Object> getTestInstance() {
-		return Optional.ofNullable(this.testInstance);
-	}
-
 	@Override
 	public void publishReportEntry(Map<String, String> values) {
 		engineExecutionListener.reportingEntryPublished(this.testDescriptor, ReportEntry.from(values));

junit-jupiter-engine/src/main/java/org/junit/jupiter/engine/descriptor/ClassExtensionContext.java

@@ -16,7 +16,7 @@
 import java.lang.reflect.Method;
 import java.util.Optional;
 
-import org.junit.jupiter.engine.execution.AbstractExtensionContext;
+import org.junit.jupiter.api.extension.ExtensionContext;
 import org.junit.jupiter.engine.execution.ThrowableCollector;
 import org.junit.platform.commons.meta.API;
 import org.junit.platform.engine.EngineExecutionListener;
@@ -28,8 +28,9 @@
 public final class ClassExtensionContext extends AbstractExtensionContext<ClassTestDescriptor> {
 
 	private final ThrowableCollector throwableCollector;
+	private Object testInstance;
 
-	public ClassExtensionContext(AbstractExtensionContext<?> parent, EngineExecutionListener engineExecutionListener,
+	public ClassExtensionContext(ExtensionContext parent, EngineExecutionListener engineExecutionListener,
 			ClassTestDescriptor testDescriptor, ThrowableCollector throwableCollector) {
 
 		super(parent, engineExecutionListener, testDescriptor);
@@ -46,6 +47,15 @@ public Optional<Class<?>> getTestClass() {
 		return Optional.of(getTestDescriptor().getTestClass());
 	}
 
+	void setTestInstance(Object testInstance) {
+		this.testInstance = testInstance;
+	}
+
+	@Override
+	public Optional<Object> getTestInstance() {
+		return Optional.ofNullable(this.testInstance);
+	}
+
 	@Override
 	public Optional<Method> getTestMethod() {
 		return Optional.empty();

junit-jupiter-engine/src/main/java/org/junit/jupiter/engine/descriptor/ClassTestDescriptor.java

@@ -22,6 +22,7 @@
 import java.util.Collections;
 import java.util.List;
 import java.util.Set;
+import java.util.function.Consumer;
 import java.util.function.Function;
 
 import org.junit.jupiter.api.TestInstance;
@@ -31,7 +32,6 @@
 import org.junit.jupiter.api.extension.Extension;
 import org.junit.jupiter.api.extension.ExtensionContext;
 import org.junit.jupiter.api.extension.TestInstancePostProcessor;
-import org.junit.jupiter.engine.execution.AbstractExtensionContext;
 import org.junit.jupiter.engine.execution.AfterEachMethodAdapter;
 import org.junit.jupiter.engine.execution.BeforeEachMethodAdapter;
 import org.junit.jupiter.engine.execution.ExecutableInvoker;
@@ -176,50 +176,39 @@ private TestInstanceProvider testInstanceProvider(JupiterEngineExecutionContext
 		if (this.lifecycle == Lifecycle.PER_CLASS) {
 			// Eagerly load test instance for BeforeAllCallbacks, if necessary,
 			// and store the instance in the ExtensionContext.
-			// Note: as a side effect, instantiateAndPostProcessTestInstance() also stores
-			// the instance it creates in the "current" extension context.
-			Object instance = instantiateAndPostProcessTestInstance(parentExecutionContext, extensionContext, registry);
-
-			// Return a TestInstanceProvider that additionally sets the test instance
-			// in the supplied child extension context (e.g., a MethodExtensionContext).
-			return (childContext, childRegistry) -> {
-				childContext.setTestInstance(instance);
-				return instance;
-			};
+			Object instance = instantiateAndPostProcessTestInstance(parentExecutionContext, extensionContext, registry,
+				extensionContext::setTestInstance);
+			return childRegistry -> instance;
 		}
 
 		// else Lifecycle.PER_METHOD
-		return (childContext, childRegistry) -> instantiateAndPostProcessTestInstance(parentExecutionContext,
-			childContext, childRegistry.orElse(registry));
+		return childRegistry -> instantiateAndPostProcessTestInstance(parentExecutionContext, extensionContext,
+			childRegistry.orElse(registry), instance -> {
+				// no extension context update required
+			});
 	}
 
-	/**
-	 * Instantiate the test instance; set the test instance in the supplied
-	 * extension context; and post process the test instance.
-	 *
-	 * @see #instantiateTestClass
-	 * @see AbstractExtensionContext#setTestInstance
-	 * @see #invokeTestInstancePostProcessors
-	 */
 	private Object instantiateAndPostProcessTestInstance(JupiterEngineExecutionContext context,
-			AbstractExtensionContext<?> extensionContext, ExtensionRegistry registry) {
+			ExtensionContext extensionContext, ExtensionRegistry registry, Consumer<Object> testInstanceConsumer) {
 
 		Object instance = instantiateTestClass(context, registry, extensionContext);
-		extensionContext.setTestInstance(instance);
-		invokeTestInstancePostProcessors(registry, extensionContext);
+		testInstanceConsumer.accept(instance);
+		invokeTestInstancePostProcessors(instance, registry, extensionContext);
 		return instance;
 	}
 
 	protected Object instantiateTestClass(JupiterEngineExecutionContext parentExecutionContext,
-			ExtensionRegistry registry, AbstractExtensionContext<?> extensionContext) {
+			ExtensionRegistry registry, ExtensionContext extensionContext) {
 
 		Constructor<?> constructor = ReflectionUtils.getDeclaredConstructor(this.testClass);
 		return executableInvoker.invoke(constructor, extensionContext, registry);
 	}
 
-	private void invokeTestInstancePostProcessors(ExtensionRegistry registry, ExtensionContext context) {
+	private void invokeTestInstancePostProcessors(Object instance, ExtensionRegistry registry,
+			ExtensionContext context) {
+
 		registry.stream(TestInstancePostProcessor.class).forEach(
-			extension -> executeAndMaskThrowable(() -> extension.postProcessTestInstance(context)));
+			extension -> executeAndMaskThrowable(() -> extension.postProcessTestInstance(instance, context)));
 	}
 
 	private void invokeBeforeAllCallbacks(JupiterEngineExecutionContext context) {
@@ -300,6 +289,7 @@ private AfterEachMethodAdapter synthesizeAfterEachMethodAdapter(Method method) {
 	}
 
 	private void invokeMethodInExtensionContext(Method method, ExtensionContext context, ExtensionRegistry registry) {
+
 		Object testInstance = context.getTestInstance().orElseThrow(() -> new JUnitException(
 			"Illegal state: test instance not present for method: " + method.toGenericString()));
 

junit-jupiter-engine/src/main/java/org/junit/jupiter/engine/descriptor/JupiterEngineDescriptor.java

@@ -13,7 +13,7 @@
 import static org.junit.jupiter.engine.extension.ExtensionRegistry.createRegistryWithDefaultExtensions;
 import static org.junit.platform.commons.meta.API.Usage.Internal;
 
-import org.junit.jupiter.engine.execution.AbstractExtensionContext;
+import org.junit.jupiter.api.extension.ExtensionContext;
 import org.junit.jupiter.engine.execution.JupiterEngineExecutionContext;
 import org.junit.jupiter.engine.extension.ExtensionRegistry;
 import org.junit.platform.commons.meta.API;
@@ -36,7 +36,7 @@ public JupiterEngineDescriptor(UniqueId uniqueId) {
 	public JupiterEngineExecutionContext prepare(JupiterEngineExecutionContext context) throws Exception {
 		ExtensionRegistry extensionRegistry = createRegistryWithDefaultExtensions(context.getConfigurationParameters());
 		EngineExecutionListener executionListener = context.getExecutionListener();
-		AbstractExtensionContext<?> extensionContext = new JupiterEngineExtensionContext(executionListener, this);
+		ExtensionContext extensionContext = new JupiterEngineExtensionContext(executionListener, this);
 
 		// @formatter:off
 		return context.extend()

junit-jupiter-engine/src/main/java/org/junit/jupiter/engine/descriptor/JupiterEngineExtensionContext.java

@@ -16,7 +16,6 @@
 import java.lang.reflect.Method;
 import java.util.Optional;
 
-import org.junit.jupiter.engine.execution.AbstractExtensionContext;
 import org.junit.platform.commons.meta.API;
 import org.junit.platform.engine.EngineExecutionListener;
 
@@ -41,6 +40,11 @@ public Optional<Class<?>> getTestClass() {
 		return Optional.empty();
 	}
 
+	@Override
+	public Optional<Object> getTestInstance() {
+		return Optional.empty();
+	}
+
 	@Override
 	public Optional<Method> getTestMethod() {
 		return Optional.empty();

junit-jupiter-engine/src/main/java/org/junit/jupiter/engine/descriptor/MethodExtensionContext.java

@@ -16,7 +16,7 @@
 import java.lang.reflect.Method;
 import java.util.Optional;
 
-import org.junit.jupiter.engine.execution.AbstractExtensionContext;
+import org.junit.jupiter.api.extension.ExtensionContext;
 import org.junit.jupiter.engine.execution.ThrowableCollector;
 import org.junit.platform.commons.meta.API;
 import org.junit.platform.engine.EngineExecutionListener;
@@ -27,13 +27,16 @@
 @API(Internal)
 public final class MethodExtensionContext extends AbstractExtensionContext<MethodTestDescriptor> {
 
+	private final Object testInstance;
+
 	private final ThrowableCollector throwableCollector;
 
-	public MethodExtensionContext(AbstractExtensionContext<?> parent, EngineExecutionListener engineExecutionListener,
-			MethodTestDescriptor testDescriptor, ThrowableCollector throwableCollector) {
+	public MethodExtensionContext(ExtensionContext parent, EngineExecutionListener engineExecutionListener,
+			MethodTestDescriptor testDescriptor, Object testInstance, ThrowableCollector throwableCollector) {
 
 		super(parent, engineExecutionListener, testDescriptor);
 
+		this.testInstance = testInstance;
 		this.throwableCollector = throwableCollector;
 	}
 
@@ -52,6 +55,11 @@ public Optional<Method> getTestMethod() {
 		return Optional.of(getTestDescriptor().getTestMethod());
 	}
 
+	@Override
+	public Optional<Object> getTestInstance() {
+		return Optional.of(this.testInstance);
+	}
+
 	@Override
 	public Optional<Throwable> getExecutionException() {
 		return Optional.ofNullable(this.throwableCollector.getThrowable());

junit-jupiter-engine/src/main/java/org/junit/jupiter/engine/descriptor/MethodTestDescriptor.java

@@ -25,7 +25,6 @@
 import org.junit.jupiter.api.extension.ExtensionContext;
 import org.junit.jupiter.api.extension.TestExecutionExceptionHandler;
 import org.junit.jupiter.api.function.Executable;
-import org.junit.jupiter.engine.execution.AbstractExtensionContext;
 import org.junit.jupiter.engine.execution.AfterEachMethodAdapter;
 import org.junit.jupiter.engine.execution.BeforeEachMethodAdapter;
 import org.junit.jupiter.engine.execution.ExecutableInvoker;
@@ -79,15 +78,10 @@ public Type getType() {
 	@Override
 	public JupiterEngineExecutionContext prepare(JupiterEngineExecutionContext context) throws Exception {
 		ExtensionRegistry registry = populateNewExtensionRegistry(context);
+		Object testInstance = context.getTestInstanceProvider().getTestInstance(Optional.of(registry));
 		ThrowableCollector throwableCollector = new ThrowableCollector();
-		AbstractExtensionContext<?> extensionContext = new MethodExtensionContext(context.getExtensionContext(),
-			context.getExecutionListener(), this, throwableCollector);
-
-		// Even though we (intentionally) ignore the return value, the following line
-		// is required since the configured TestInstanceProvider is responsible for
-		// setting the test instance in the supplied extension context.
-		// See ClassTestDescriptor#testInstanceProvider(...) for details.
-		context.getTestInstanceProvider().getTestInstance(extensionContext, Optional.of(registry));
+		ExtensionContext extensionContext = new MethodExtensionContext(context.getExtensionContext(),
+			context.getExecutionListener(), this, testInstance, throwableCollector);
 
 		// @formatter:off
 		return context.extend()
@@ -105,7 +99,6 @@ protected ExtensionRegistry populateNewExtensionRegistry(JupiterEngineExecutionC
 	@Override
 	public JupiterEngineExecutionContext execute(JupiterEngineExecutionContext context,
 			DynamicTestExecutor dynamicTestExecutor) throws Exception {
-
 		ThrowableCollector throwableCollector = context.getThrowableCollector();
 
 		// @formatter:off

junit-jupiter-engine/src/main/java/org/junit/jupiter/engine/descriptor/NestedClassTestDescriptor.java

@@ -16,7 +16,7 @@
 import java.util.Optional;
 import java.util.Set;
 
-import org.junit.jupiter.engine.execution.AbstractExtensionContext;
+import org.junit.jupiter.api.extension.ExtensionContext;
 import org.junit.jupiter.engine.execution.ExecutableInvoker;
 import org.junit.jupiter.engine.execution.JupiterEngineExecutionContext;
 import org.junit.jupiter.engine.extension.ExtensionRegistry;
@@ -58,11 +58,11 @@ public final Set<TestTag> getTags() {
 
 	@Override
 	protected Object instantiateTestClass(JupiterEngineExecutionContext parentExecutionContext,
-			ExtensionRegistry registry, AbstractExtensionContext<?> extensionContext) {
+			ExtensionRegistry registry, ExtensionContext extensionContext) {
 
 		// Extensions registered for nested classes and below are not to be used for instantiating outer classes
 		Optional<ExtensionRegistry> childExtensionRegistryForOuterInstance = Optional.empty();
-		Object outerInstance = parentExecutionContext.getTestInstanceProvider().getTestInstance(extensionContext,
+		Object outerInstance = parentExecutionContext.getTestInstanceProvider().getTestInstance(
 			childExtensionRegistryForOuterInstance);
 		Constructor<?> constructor = ReflectionUtils.getDeclaredConstructor(getTestClass());
 		return executableInvoker.invoke(constructor, outerInstance, extensionContext, registry);