Use @DirtiesContext to avoid unwanted context caching in the tests

We rarely use the same configuration in multiple test classes, but
Spring’s Test framework caches each context by default. For projects
with large numbers of integration tests, this can lead to tens of
contexts being cached. This increases memory usage, live thread count,
etc for no benefit.

This commit adds @DirtiesContext to the integration tests in
spring-boot, spring-boot-autoconfigure, and spring-boot-actuator so
that the context is closed once the test class has completed.

See gh-5141

spring-boot-actuator/src/test/java/org/springframework/boot/actuate/endpoint/mvc/EnvironmentMvcEndpointTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2015 the original author or authors.
+ * 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.
@@ -39,6 +39,7 @@ import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Import;
 import org.springframework.core.env.ConfigurableEnvironment;
 import org.springframework.core.env.MapPropertySource;
+import org.springframework.test.annotation.DirtiesContext;
 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
 import org.springframework.test.context.web.WebAppConfiguration;
 import org.springframework.test.web.servlet.MockMvc;
@@ -57,6 +58,7 @@ import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.
  * @author Andy Wilkinson
  */
 @RunWith(SpringJUnit4ClassRunner.class)
+@DirtiesContext
 @SpringApplicationConfiguration(TestConfiguration.class)
 @WebAppConfiguration
 public class EnvironmentMvcEndpointTests {

spring-boot-actuator/src/test/java/org/springframework/boot/actuate/endpoint/mvc/JolokiaMvcEndpointContextPathTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2015 the original author or authors.
+ * Copyright 2013-2016 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.
@@ -35,6 +35,7 @@ import org.springframework.context.ApplicationContextInitializer;
 import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Import;
+import org.springframework.test.annotation.DirtiesContext;
 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
 import org.springframework.test.context.web.WebAppConfiguration;
 import org.springframework.test.web.servlet.MockMvc;
@@ -52,6 +53,7 @@ import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.
  * @author Dave Syer
  */
 @RunWith(SpringJUnit4ClassRunner.class)
+@DirtiesContext
 @SpringApplicationConfiguration(classes = {
 		Config.class }, initializers = ContextPathListener.class)
 @WebAppConfiguration

spring-boot-actuator/src/test/java/org/springframework/boot/actuate/endpoint/mvc/JolokiaMvcEndpointTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2015 the original author or authors.
+ * Copyright 2013-2016 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.
@@ -35,6 +35,7 @@ import org.springframework.boot.test.SpringApplicationConfiguration;
 import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Import;
+import org.springframework.test.annotation.DirtiesContext;
 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
 import org.springframework.test.context.web.WebAppConfiguration;
 import org.springframework.test.web.servlet.MockMvc;
@@ -55,6 +56,7 @@ import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.
  * @author Dave Syer
  */
 @RunWith(SpringJUnit4ClassRunner.class)
+@DirtiesContext
 @SpringApplicationConfiguration(Config.class)
 @WebAppConfiguration
 public class JolokiaMvcEndpointTests {

spring-boot-actuator/src/test/java/org/springframework/boot/actuate/endpoint/mvc/MetricsMvcEndpointTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2015 the original author or authors.
+ * 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.
@@ -38,6 +38,7 @@ import org.springframework.boot.test.SpringApplicationConfiguration;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Import;
+import org.springframework.test.annotation.DirtiesContext;
 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
 import org.springframework.test.context.web.WebAppConfiguration;
 import org.springframework.test.web.servlet.MockMvc;
@@ -57,6 +58,7 @@ import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.
  * @author Sergei Egorov
  */
 @RunWith(SpringJUnit4ClassRunner.class)
+@DirtiesContext
 @SpringApplicationConfiguration(TestConfiguration.class)
 @WebAppConfiguration
 public class MetricsMvcEndpointTests {