Print AutoConfigureReport on test failures

Add a TestExecutionListener to print the auto-configuration report
when a test cannot load.

See gh-4901

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

@@ -0,0 +1,59 @@
+/*
+ * 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 org.springframework.boot.autoconfigure.condition.ConditionEvaluationReport;
+import org.springframework.boot.autoconfigure.logging.ConditionEvalutionReportMessage;
+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.
+ *
+ * @author Phillip Webb
+ */
+class AutoConfigureReportTestExecutionListener extends AbstractTestExecutionListener {
+
+	private DependencyInjectionTestExecutionListener delegate = new DependencyInjectionTestExecutionListener();
+
+	@Override
+	public int getOrder() {
+		return this.delegate.getOrder() - 1;
+	}
+
+	@Override
+	public void prepareTestInstance(TestContext testContext) throws Exception {
+		try {
+			this.delegate.prepareTestInstance(testContext);
+		}
+		catch (Exception ex) {
+			ApplicationContext context = testContext.getApplicationContext();
+			if (context instanceof ConfigurableApplicationContext) {
+				ConditionEvaluationReport report = ConditionEvaluationReport
+						.get(((ConfigurableApplicationContext) context).getBeanFactory());
+				System.err.println(new ConditionEvalutionReportMessage(report));
+			}
+			throw ex;
+		}
+	}
+
+}

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

@@ -0,0 +1,81 @@
+/*
+ * 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 org.junit.Rule;
+import org.junit.Test;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.ImportAutoConfiguration;
+import org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration;
+import org.springframework.boot.test.rule.OutputCapture;
+import org.springframework.context.ConfigurableApplicationContext;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.core.Ordered;
+import org.springframework.test.context.TestContext;
+import org.springframework.test.context.support.DependencyInjectionTestExecutionListener;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.hamcrest.Matchers.containsString;
+import static org.mockito.BDDMockito.given;
+import static org.mockito.Mockito.mock;
+
+/**
+ * Tests for {@link AutoConfigureReportTestExecutionListener}.
+ *
+ * @author Phillip Webb
+ */
+public class AutoConfigureReportTestExecutionListenerTests {
+
+	@Rule
+	public OutputCapture out = new OutputCapture();
+
+	private AutoConfigureReportTestExecutionListener reportListener = new AutoConfigureReportTestExecutionListener();
+
+	@Test
+	public void orderShouldBeBeforeDependencyInjectionTestExecutionListener()
+			throws Exception {
+		Ordered injectionListener = new DependencyInjectionTestExecutionListener();
+		assertThat(this.reportListener.getOrder())
+				.isLessThan(injectionListener.getOrder());
+	}
+
+	@Test
+	public void prepareFialingTestInstanceShouldPrintReport() throws Exception {
+		TestContext testContext = mock(TestContext.class);
+		given(testContext.getTestInstance()).willThrow(new IllegalStateException());
+		SpringApplication application = new SpringApplication(Config.class);
+		application.setWebEnvironment(false);
+		ConfigurableApplicationContext applicationContext = application.run();
+		given(testContext.getApplicationContext()).willReturn(applicationContext);
+		try {
+			this.reportListener.prepareTestInstance(testContext);
+		}
+		catch (IllegalStateException ex) {
+			// Expected
+		}
+		this.out.expect(containsString("AUTO-CONFIGURATION REPORT"));
+		this.out.expect(containsString("Positive matches"));
+		this.out.expect(containsString("Negative matches"));
+	}
+
+	@Configuration
+	@ImportAutoConfiguration(JacksonAutoConfiguration.class)
+	static class Config {
+	}
+
+}