Ensure test fails for the correct reason

Prior to this commit, a dynamic test in
FailingBeforeAndAfterMethodsSpringExtensionTestCase was failing but for
the wrong reason. Namely, the @configuration class was private which
resulted in an IllegalStateException being thrown, when in fact
an AssertionFailedError was expected.

This commit addresses this by introducing an explicit check for an
AssertionFailedError.

Issue: SPR-4365

Author: sbrannen

spring-test/src/test/java/org/springframework/test/context/junit/jupiter/FailingBeforeAndAfterMethodsSpringExtensionTestCase.java

@@ -16,6 +16,8 @@
 
 package org.springframework.test.context.junit.jupiter;
 
+import java.util.ArrayList;
+import java.util.List;
 import java.util.stream.Stream;
 
 import javax.sql.DataSource;
@@ -24,11 +26,15 @@
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.TestFactory;
 import org.junit.jupiter.api.extension.ExtendWith;
+import org.junit.platform.engine.TestExecutionResult;
 import org.junit.platform.launcher.Launcher;
+import org.junit.platform.launcher.TestIdentifier;
 import org.junit.platform.launcher.core.LauncherFactory;
 import org.junit.platform.launcher.listeners.SummaryGeneratingListener;
 import org.junit.platform.launcher.listeners.TestExecutionSummary;
 
+import org.opentest4j.AssertionFailedError;
+
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.jdbc.datasource.DataSourceTransactionManager;
@@ -85,7 +91,7 @@ Stream<DynamicTest> generateTests() throws Exception {
 
 	private void runTestAndAssertCounters(Class<?> testClass) {
 		Launcher launcher = LauncherFactory.create();
-		SummaryGeneratingListener listener = new SummaryGeneratingListener();
+		ExceptionTrackingListener listener = new ExceptionTrackingListener();
 		launcher.registerTestExecutionListeners(listener);
 
 		launcher.execute(request().selectors(selectClass(testClass)).build());
@@ -106,6 +112,18 @@ private void runTestAndAssertCounters(Class<?> testClass) {
 			() -> assertEquals(expectedFailedCount, summary.getTestsFailedCount(), () -> name + ": tests failed")
 		);
 		// @formatter:on
+
+		// Ensure it was an AssertionFailedError that failed the test and not
+		// something else like an error in the @Configuration class, etc.
+		if (expectedFailedCount > 0) {
+			assertEquals(1, listener.exceptions.size(), "exceptions expected");
+			Throwable exception = listener.exceptions.get(0);
+			if (!(exception instanceof AssertionFailedError)) {
+				throw new AssertionFailedError(
+					exception.getClass().getName() + " is not an instance of " + AssertionFailedError.class.getName(),
+					exception);
+			}
+		}
 	}
 
 	private int getExpectedStartedCount(Class<?> testClass) {
@@ -247,8 +265,9 @@ void afterTransaction() {
 		}
 	}
 
+	// Must not be private.
 	@Configuration
-	private static class DatabaseConfig {
+	static class DatabaseConfig {
 
 		@Bean
 		PlatformTransactionManager transactionManager() {
@@ -261,4 +280,16 @@ DataSource dataSource() {
 		}
 	}
 
+	private static class ExceptionTrackingListener extends SummaryGeneratingListener {
+
+		List<Throwable> exceptions = new ArrayList<>();
+
+
+		@Override
+		public void executionFinished(TestIdentifier testIdentifier, TestExecutionResult testExecutionResult) {
+			super.executionFinished(testIdentifier, testExecutionResult);
+			testExecutionResult.getThrowable().ifPresent(exceptions::add);
+		}
+	}
+
 }