Ensure test @PostConstructs are only called once

Rename AutoConfigureReportTestExecutionListener to
SpringBootDependencyInjectionTestExecutionListener and ensure that it
replaces any existing DependencyInjectionTestExecutionListener.

Prior to this commit the registration of two DependencyInjection
listeners would cause @PostConstruct methods on tests to be called
twice.

In order to allow the standard DependencyInjectionTestExecutionListener
to be removed a new DefaultTestExecutionListenersPostProcessor interface
has been introduced.

Fixes gh-6874

spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure/SpringBootDependencyInjectionTestExecutionListener.java

@@ -16,34 +16,32 @@
 
 package org.springframework.boot.test.autoconfigure;
 
+import java.util.LinkedHashSet;
+import java.util.Set;
+
 import org.springframework.boot.autoconfigure.condition.ConditionEvaluationReport;
 import org.springframework.boot.autoconfigure.logging.ConditionEvaluationReportMessage;
+import org.springframework.boot.test.context.DefaultTestExecutionListenersPostProcessor;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.test.context.TestContext;
 import org.springframework.test.context.TestExecutionListener;
-import org.springframework.test.context.support.AbstractTestExecutionListener;
 import org.springframework.test.context.support.DependencyInjectionTestExecutionListener;
 
 /**
- * {@link TestExecutionListener} to print the {@link ConditionEvaluationReport} when the
- * context cannot be prepared.
+ * Alternative {@link DependencyInjectionTestExecutionListener} prints the
+ * {@link ConditionEvaluationReport} when the context cannot be prepared.
  *
  * @author Phillip Webb
+ * @since 1.4.1
  */
-class AutoConfigureReportTestExecutionListener extends AbstractTestExecutionListener {
-
-	private DependencyInjectionTestExecutionListener delegate = new DependencyInjectionTestExecutionListener();
-
-	@Override
-	public int getOrder() {
-		return this.delegate.getOrder() - 1;
-	}
+public class SpringBootDependencyInjectionTestExecutionListener
+		extends DependencyInjectionTestExecutionListener {
 
 	@Override
 	public void prepareTestInstance(TestContext testContext) throws Exception {
 		try {
-			this.delegate.prepareTestInstance(testContext);
+			super.prepareTestInstance(testContext);
 		}
 		catch (Exception ex) {
 			ApplicationContext context = testContext.getApplicationContext();
@@ -56,4 +54,22 @@ class AutoConfigureReportTestExecutionListener extends AbstractTestExecutionList
 		}
 	}
 
+	static class PostProcessor implements DefaultTestExecutionListenersPostProcessor {
+
+		@Override
+		public Set<Class<? extends TestExecutionListener>> postProcessDefaultTestExecutionListeners(
+				Set<Class<? extends TestExecutionListener>> listeners) {
+			Set<Class<? extends TestExecutionListener>> updated = new LinkedHashSet<Class<? extends TestExecutionListener>>(
+					listeners.size());
+			for (Class<? extends TestExecutionListener> listener : listeners) {
+				updated.add(
+						listener.equals(DependencyInjectionTestExecutionListener.class)
+								? SpringBootDependencyInjectionTestExecutionListener.class
+								: listener);
+			}
+			return updated;
+		}
+
+	}
+
 }

spring-boot-test-autoconfigure/src/main/resources/META-INF/spring.factories

@@ -66,6 +66,10 @@ org.springframework.boot.autoconfigure.thymeleaf.ThymeleafAutoConfiguration,\
 org.springframework.boot.autoconfigure.web.HttpMessageConvertersAutoConfiguration,\
 org.springframework.boot.autoconfigure.web.WebMvcAutoConfiguration
 
+# DefaultTestExecutionListenersPostProcessors
+org.springframework.boot.test.context.DefaultTestExecutionListenersPostProcessor=\
+org.springframework.boot.test.autoconfigure.SpringBootDependencyInjectionTestExecutionListener$PostProcessor
+
 # Spring Test ContextCustomizerFactories
 org.springframework.test.context.ContextCustomizerFactory=\
 org.springframework.boot.test.autoconfigure.OverrideAutoConfigurationContextCustomizerFactory,\
@@ -74,6 +78,5 @@ org.springframework.boot.test.autoconfigure.properties.PropertyMappingContextCus
 
 # Test Execution Listeners
 org.springframework.test.context.TestExecutionListener=\
-org.springframework.boot.test.autoconfigure.AutoConfigureReportTestExecutionListener,\
 org.springframework.boot.test.autoconfigure.restdocs.RestDocsTestExecutionListener,\
 org.springframework.boot.test.autoconfigure.web.client.MockRestServiceServerResetTestExecutionListener

spring-boot-test-autoconfigure/src/test/java/org/springframework/boot/test/autoconfigure/SpringBootDependencyInjectionTestExecutionListenerPostConstructIntegrationTests.java

@@ -0,0 +1,64 @@
+/*
+ * Copyright 2012-2016 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.test.autoconfigure;
+
+import java.io.PrintWriter;
+import java.io.StringWriter;
+import java.util.ArrayList;
+import java.util.List;
+
+import javax.annotation.PostConstruct;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.test.context.junit4.SpringRunner;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Integration tests for {@link SpringBootDependencyInjectionTestExecutionListener}.
+ *
+ * @author Phillip Webb
+ */
+@RunWith(SpringRunner.class)
+@SpringBootTest
+public class SpringBootDependencyInjectionTestExecutionListenerPostConstructIntegrationTests {
+
+	private List<String> calls = new ArrayList<String>();
+
+	@PostConstruct
+	public void postConstruct() {
+		StringWriter writer = new StringWriter();
+		new RuntimeException().printStackTrace(new PrintWriter(writer));
+		this.calls.add(writer.toString());
+	}
+
+	@Test
+	public void postConstructShouldBeInvokedOnlyOnce() throws Exception {
+		// gh-6874
+		assertThat(this.calls).hasSize(1);
+	}
+
+	@Configuration
+	static class Config {
+
+	}
+
+}

spring-boot-test-autoconfigure/src/test/java/org/springframework/boot/test/autoconfigure/SpringBootDependencyInjectionTestExecutionListenerTests.java

@@ -35,23 +35,23 @@ import static org.mockito.BDDMockito.given;
 import static org.mockito.Mockito.mock;
 
 /**
- * Tests for {@link AutoConfigureReportTestExecutionListener}.
+ * Tests for {@link SpringBootDependencyInjectionTestExecutionListener}.
  *
  * @author Phillip Webb
  */
-public class AutoConfigureReportTestExecutionListenerTests {
+public class SpringBootDependencyInjectionTestExecutionListenerTests {
 
 	@Rule
 	public OutputCapture out = new OutputCapture();
 
-	private AutoConfigureReportTestExecutionListener reportListener = new AutoConfigureReportTestExecutionListener();
+	private SpringBootDependencyInjectionTestExecutionListener reportListener = new SpringBootDependencyInjectionTestExecutionListener();
 
 	@Test
-	public void orderShouldBeBeforeDependencyInjectionTestExecutionListener()
+	public void orderShouldBeSameAsDependencyInjectionTestExecutionListener()
 			throws Exception {
 		Ordered injectionListener = new DependencyInjectionTestExecutionListener();
 		assertThat(this.reportListener.getOrder())
-				.isLessThan(injectionListener.getOrder());
+				.isEqualTo(injectionListener.getOrder());
 	}
 
 	@Test

spring-boot-test/src/main/java/org/springframework/boot/test/context/DefaultTestExecutionListenersPostProcessor.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2012-2016 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.test.context;
+
+import java.util.Set;
+
+import org.springframework.test.context.TestExecutionListener;
+
+/**
+ * Callback interface trigger from {@link SpringBootTestContextBootstrapper} that can be
+ * used to post-process the list of default {@link TestExecutionListener} classes to be
+ * used by a test. Can be used to add or remove existing listener classes.
+ *
+ * @author Phillip Webb
+ * @since 1.4.1
+ * @see SpringBootTest
+ */
+public interface DefaultTestExecutionListenersPostProcessor {
+
+	/**
+	 * Post process the list of default {@link TestExecutionListener} classes to be used.
+	 * @param listeners the source listeners
+	 * @return the actual listeners that should be used
+	 */
+	Set<Class<? extends TestExecutionListener>> postProcessDefaultTestExecutionListeners(
+			Set<Class<? extends TestExecutionListener>> listeners);
+
+}

spring-boot-test/src/main/java/org/springframework/boot/test/context/SpringBootTestContextBootstrapper.java

@@ -19,6 +19,7 @@ package org.springframework.boot.test.context;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
+import java.util.Set;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
@@ -27,11 +28,13 @@ import org.springframework.boot.SpringBootConfiguration;
 import org.springframework.boot.test.context.SpringBootTest.WebEnvironment;
 import org.springframework.core.annotation.AnnotatedElementUtils;
 import org.springframework.core.env.Environment;
+import org.springframework.core.io.support.SpringFactoriesLoader;
 import org.springframework.test.context.ContextConfigurationAttributes;
 import org.springframework.test.context.ContextLoader;
 import org.springframework.test.context.MergedContextConfiguration;
 import org.springframework.test.context.TestContext;
 import org.springframework.test.context.TestContextBootstrapper;
+import org.springframework.test.context.TestExecutionListener;
 import org.springframework.test.context.support.DefaultTestContextBootstrapper;
 import org.springframework.test.context.web.WebAppConfiguration;
 import org.springframework.test.context.web.WebMergedContextConfiguration;
@@ -82,6 +85,18 @@ public class SpringBootTestContextBootstrapper extends DefaultTestContextBootstr
 		return context;
 	}
 
+	@Override
+	protected Set<Class<? extends TestExecutionListener>> getDefaultTestExecutionListenerClasses() {
+		Set<Class<? extends TestExecutionListener>> listeners = super.getDefaultTestExecutionListenerClasses();
+		List<DefaultTestExecutionListenersPostProcessor> postProcessors = SpringFactoriesLoader
+				.loadFactories(DefaultTestExecutionListenersPostProcessor.class,
+						getClass().getClassLoader());
+		for (DefaultTestExecutionListenersPostProcessor postProcessor : postProcessors) {
+			listeners = postProcessor.postProcessDefaultTestExecutionListeners(listeners);
+		}
+		return listeners;
+	}
+
 	@Override
 	protected ContextLoader resolveContextLoader(Class<?> testClass,
 			List<ContextConfigurationAttributes> configAttributesList) {

spring-boot-test/src/test/java/org/springframework/boot/test/context/bootstrap/SpringBootTestContextBootstrapperTests.java

@@ -46,6 +46,8 @@ public class SpringBootTestContextBootstrapperTests {
 	@Autowired
 	private SpringBootTestContextBootstrapperExampleConfig config;
 
+	public boolean defaultTestExecutionListenersPostProcessorCalled;
+
 	@Test
 	public void findConfigAutomatically() throws Exception {
 		assertThat(this.config).isNotNull();
@@ -61,6 +63,12 @@ public class SpringBootTestContextBootstrapperTests {
 		assertThat(this.context.getBean(ExampleBean.class)).isNotNull();
 	}
 
+	@Test
+	public void defaultTestExecutionListenersPostProcessorShouldBeCalled()
+			throws Exception {
+		assertThat(this.defaultTestExecutionListenersPostProcessorCalled).isTrue();
+	}
+
 	@TestConfiguration
 	static class TestConfig {
 
@@ -79,4 +87,5 @@ public class SpringBootTestContextBootstrapperTests {
 	static class ExampleTestComponent {
 
 	}
+
 }

spring-boot-test/src/test/java/org/springframework/boot/test/context/bootstrap/TestDefaultTestExecutionListenersPostProcessor.java

@@ -0,0 +1,54 @@
+/*
+ * Copyright 2012-2016 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.test.context.bootstrap;
+
+import java.util.Set;
+
+import org.springframework.boot.test.context.DefaultTestExecutionListenersPostProcessor;
+import org.springframework.test.context.TestContext;
+import org.springframework.test.context.TestExecutionListener;
+import org.springframework.test.context.support.AbstractTestExecutionListener;
+
+/**
+ * Test {@link DefaultTestExecutionListenersPostProcessor}.
+ *
+ * @author Phillip Webb
+ */
+public class TestDefaultTestExecutionListenersPostProcessor
+		implements DefaultTestExecutionListenersPostProcessor {
+
+	@Override
+	public Set<Class<? extends TestExecutionListener>> postProcessDefaultTestExecutionListeners(
+			Set<Class<? extends TestExecutionListener>> listeners) {
+		listeners.add(ExampleTestExecutionListener.class);
+		return listeners;
+	}
+
+	static class ExampleTestExecutionListener extends AbstractTestExecutionListener {
+
+		@Override
+		public void prepareTestInstance(TestContext testContext) throws Exception {
+			Object testInstance = testContext.getTestInstance();
+			if (testInstance instanceof SpringBootTestContextBootstrapperTests) {
+				SpringBootTestContextBootstrapperTests test = (SpringBootTestContextBootstrapperTests) testInstance;
+				test.defaultTestExecutionListenersPostProcessorCalled = true;
+			}
+		}
+
+	}
+
+}

spring-boot-test/src/test/resources/META-INF/spring.factories

@@ -0,0 +1,2 @@
+org.springframework.boot.test.context.DefaultTestExecutionListenersPostProcessor=\
+org.springframework.boot.test.context.bootstrap.TestDefaultTestExecutionListenersPostProcessor