GH-191 - Prevent premature access of ApplicationContext from ParameterResolver implementations.

We now avoid accessing the ApplicationContext from a BeforeAllCallback as this might cause the context initialization before other extensions had time to kick in.

Author: odrotbohm

spring-modulith-test/src/main/java/org/springframework/modulith/test/PublishedEventsParameterResolver.java

@@ -18,7 +18,6 @@
 import java.util.function.Function;
 
 import org.junit.jupiter.api.extension.AfterEachCallback;
-import org.junit.jupiter.api.extension.BeforeAllCallback;
 import org.junit.jupiter.api.extension.ExtensionContext;
 import org.junit.jupiter.api.extension.ParameterContext;
 import org.junit.jupiter.api.extension.ParameterResolver;
@@ -35,7 +34,7 @@
  *
  * @author Oliver Drotbohm
  */
-class PublishedEventsParameterResolver implements ParameterResolver, BeforeAllCallback, AfterEachCallback {
+class PublishedEventsParameterResolver implements ParameterResolver, AfterEachCallback {
 
 	private static final boolean ASSERT_J_PRESENT = ClassUtils.isPresent("org.assertj.core.api.Assert",
 			PublishedEventsParameterResolver.class.getClassLoader());
@@ -51,32 +50,6 @@ class PublishedEventsParameterResolver implements ParameterResolver, BeforeAllCa
 		this.lookup = supplier;
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.junit.jupiter.api.extension.BeforeAllCallback#beforeAll(org.junit.jupiter.api.extension.ExtensionContext)
-	 */
-	@Override
-	public void beforeAll(ExtensionContext extensionContext) {
-
-		ApplicationContext context = lookup.apply(extensionContext);
-
-		if (!(context instanceof AbstractApplicationContext aac)) {
-			throw new IllegalStateException();
-		}
-
-		listener = aac.getApplicationListeners().stream()
-				.filter(ThreadBoundApplicationListenerAdapter.class::isInstance)
-				.map(ThreadBoundApplicationListenerAdapter.class::cast)
-				.findFirst()
-				.orElseGet(() -> {
-
-					var adapter = new ThreadBoundApplicationListenerAdapter();
-					aac.addApplicationListener(adapter);
-
-					return adapter;
-				});
-	}
-
 	/*
 	 * (non-Javadoc)
 	 * @see org.junit.jupiter.api.extension.ParameterResolver#supportsParameter(org.junit.jupiter.api.extension.ParameterContext, org.junit.jupiter.api.extension.ExtensionContext)
@@ -105,18 +78,47 @@ public PublishedEvents resolveParameter(ParameterContext parameterContext, Exten
 				? new DefaultAssertablePublishedEvents()
 				: new DefaultPublishedEvents();
 
+		initializeListener(extensionContext);
 		listener.registerDelegate(publishedEvents);
 
 		return publishedEvents;
 	}
 
+	private void initializeListener(ExtensionContext extensionContext) {
+
+		if (listener != null) {
+			return;
+		}
+
+		ApplicationContext context = lookup.apply(extensionContext);
+
+		if (!(context instanceof AbstractApplicationContext aac)) {
+			throw new IllegalStateException();
+		}
+
+		listener = aac.getApplicationListeners().stream()
+				.filter(ThreadBoundApplicationListenerAdapter.class::isInstance)
+				.map(ThreadBoundApplicationListenerAdapter.class::cast)
+				.findFirst()
+				.orElseGet(() -> {
+
+					var adapter = new ThreadBoundApplicationListenerAdapter();
+					aac.addApplicationListener(adapter);
+
+					return adapter;
+				});
+	}
+
 	/*
 	 * (non-Javadoc)
 	 * @see org.junit.jupiter.api.extension.AfterEachCallback#afterEach(org.junit.jupiter.api.extension.ExtensionContext)
 	 */
 	@Override
 	public void afterEach(ExtensionContext context) {
-		listener.unregisterDelegate();
+
+		if (listener != null) {
+			listener.unregisterDelegate();
+		}
 	}
 
 	/**

spring-modulith-test/src/main/java/org/springframework/modulith/test/ScenarioParameterResolver.java

@@ -15,7 +15,7 @@
  */
 package org.springframework.modulith.test;
 
-import org.junit.jupiter.api.extension.BeforeAllCallback;
+import org.junit.jupiter.api.extension.AfterEachCallback;
 import org.junit.jupiter.api.extension.ExtensionContext;
 import org.junit.jupiter.api.extension.ParameterContext;
 import org.junit.jupiter.api.extension.ParameterResolutionException;
@@ -30,7 +30,7 @@
  *
  * @author Oliver Drotbohm
  */
-class ScenarioParameterResolver implements ParameterResolver, BeforeAllCallback {
+class ScenarioParameterResolver implements ParameterResolver, AfterEachCallback {
 
 	private static final String MISSING_TRANSACTION_TEMPLATE = "To use a Scenario in an integration test you need to define a bean of type TransactionTemplate! Please check your ApplicationContext setup.";
 
@@ -43,6 +43,15 @@ public ScenarioParameterResolver() {
 		this.delegate = new PublishedEventsParameterResolver();
 	}
 
+	/*
+	 * (non-Javadoc)
+	 * @see org.junit.jupiter.api.extension.AfterEachCallback#afterEach(org.junit.jupiter.api.extension.ExtensionContext)
+	 */
+	@Override
+	public void afterEach(ExtensionContext context) throws Exception {
+		delegate.afterEach(context);
+	}
+
 	/*
 	 * (non-Javadoc)
 	 * @see org.junit.jupiter.api.extension.ParameterResolver#supportsParameter(org.junit.jupiter.api.extension.ParameterContext, org.junit.jupiter.api.extension.ExtensionContext)
@@ -56,15 +65,6 @@ public boolean supportsParameter(ParameterContext parameterContext, ExtensionCon
 		return Scenario.class.isAssignableFrom(type);
 	}
 
-	/*
-	 * (non-Javadoc)
-	 * @see org.junit.jupiter.api.extension.BeforeAllCallback#beforeAll(org.junit.jupiter.api.extension.ExtensionContext)
-	 */
-	@Override
-	public void beforeAll(ExtensionContext context) throws Exception {
-		delegate.beforeAll(context);
-	}
-
 	/*
 	 * (non-Javadoc)
 	 * @see org.junit.jupiter.api.extension.ParameterResolver#resolveParameter(org.junit.jupiter.api.extension.ParameterContext, org.junit.jupiter.api.extension.ExtensionContext)

spring-modulith-test/src/test/java/org/springframework/modulith/test/PublishedEventsParameterResolverUnitTests.java

@@ -56,8 +56,6 @@ void createsThreadBoundPublishedEvents() throws Exception {
 		PublishedEventsParameterResolver resolver = new PublishedEventsParameterResolver(__ -> context);
 		context.refresh();
 
-		resolver.beforeAll(null);
-
 		Map<String, PublishedEvents> allEvents = new ConcurrentHashMap<>();
 		List<String> keys = Arrays.asList("first", "second", "third");
 		CountDownLatch latch = new CountDownLatch(3);
@@ -75,7 +73,6 @@ void createsThreadBoundPublishedEvents() throws Exception {
 				latch.countDown();
 
 			}).start();
-
 		}
 
 		latch.await(50, TimeUnit.MILLISECONDS);