Spring TestでSpring MVCのテストを実行する時にハマったこと

# SpringのテストでJUnitからSpringの機能を使うためのアノテーションは2つある

**`@SpringJunitConfig`**
**`@SpringJunitWebConfig`**

SpringMVCを使う(`@EnableWebMvc`)場合は、**`@SpringJunitWebConfig`**を利用すること！

## ハマったこと

Testクラスに`@SpringJunitConfig`をつけてた、Controllerクラスのテストを実行しようとすると、こんな感じでExceptionが出力された。
`Caused by: java.lang.IllegalStateException: No ServletContext set`と出てたので、Productionコード側で設定漏れがあったと勘違いしていろいろ調べてしまった。
このテストクラスをスキップしてProductionコードをデプロイしたら普通に動いたので、テストコードが怪しいと気づき調べて見つけた。

```
2019-02-11 17:28:52,797 [main] ERROR o.s.test.context.TestContextManager - Caught exception while allowing TestExecutionListener [org.springframework.test.context.support.DependencyInjectionTestExecutionListener@295cf707] to prepare test instance [com.demo.web.controller.MembersDiaryControllerTest@327ed9f5]
java.lang.IllegalStateException: Failed to load ApplicationContext
	at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:125)
	at org.springframework.test.context.support.DefaultTestContext.getApplicationContext(DefaultTestContext.java:108)
	at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.injectDependencies(DependencyInjectionTestExecutionListener.java:118)
	at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.prepareTestInstance(DependencyInjectionTestExecutionListener.java:83)
	at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:246)
	at org.springframework.test.context.junit.jupiter.SpringExtension.postProcessTestInstance(SpringExtension.java:97)
	at org.junit.jupiter.engine.descriptor.ClassTestDescriptor.lambda$invokeTestInstancePostProcessors$5(ClassTestDescriptor.java:349)
	at org.junit.jupiter.engine.descriptor.JupiterTestDescriptor.executeAndMaskThrowable(JupiterTestDescriptor.java:215)
	at org.junit.jupiter.engine.descriptor.ClassTestDescriptor.lambda$invokeTestInstancePostProcessors$6(ClassTestDescriptor.java:349)
	at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:195)
	at java.base/java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:177)
	at java.base/java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1654)
	at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:484)
	at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474)
	at java.base/java.util.stream.StreamSpliterators$WrappingSpliterator.forEachRemaining(StreamSpliterators.java:312)
	at java.base/java.util.stream.Streams$ConcatSpliterator.forEachRemaining(Streams.java:735)
	at java.base/java.util.stream.Streams$ConcatSpliterator.forEachRemaining(Streams.java:734)
	at java.base/java.util.stream.ReferencePipeline$Head.forEach(ReferencePipeline.java:658)
	at org.junit.jupiter.engine.descriptor.ClassTestDescriptor.invokeTestInstancePostProcessors(ClassTestDescriptor.java:348)
	at org.junit.jupiter.engine.descriptor.ClassTestDescriptor.instantiateAndPostProcessTestInstance(ClassTestDescriptor.java:270)
	at org.junit.jupiter.engine.descriptor.ClassTestDescriptor.lambda$testInstanceProvider$2(ClassTestDescriptor.java:259)
	at org.junit.jupiter.engine.descriptor.ClassTestDescriptor.lambda$testInstanceProvider$3(ClassTestDescriptor.java:263)
	at java.base/java.util.Optional.orElseGet(Optional.java:369)
	at org.junit.jupiter.engine.descriptor.ClassTestDescriptor.lambda$testInstanceProvider$4(ClassTestDescriptor.java:262)
	at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.prepare(TestMethodTestDescriptor.java:82)
	at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.prepare(TestMethodTestDescriptor.java:59)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$prepare$0(NodeTestTask.java:83)
	at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:72)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.prepare(NodeTestTask.java:83)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:69)
	at java.base/java.util.ArrayList.forEach(ArrayList.java:1540)
	at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:38)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$4(NodeTestTask.java:112)
	at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:72)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:98)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:74)
	at java.base/java.util.ArrayList.forEach(ArrayList.java:1540)
	at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:38)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$4(NodeTestTask.java:112)
	at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:72)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:98)
	at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:74)
	at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.submit(SameThreadHierarchicalTestExecutorService.java:32)
	at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor.execute(HierarchicalTestExecutor.java:57)
	at org.junit.platform.engine.support.hierarchical.HierarchicalTestEngine.execute(HierarchicalTestEngine.java:51)
	at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:220)
	at org.junit.platform.launcher.core.DefaultLauncher.lambda$execute$6(DefaultLauncher.java:188)
	at org.junit.platform.launcher.core.DefaultLauncher.withInterceptedStreams(DefaultLauncher.java:202)
	at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:181)
	at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:128)
	at com.intellij.junit5.JUnit5IdeaTestRunner.startRunnerWithArgs(JUnit5IdeaTestRunner.java:74)
	at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:47)
	at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)
	at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'resourceHandlerMapping' defined in org.springframework.web.servlet.config.annotation.DelegatingWebMvcConfiguration: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.web.servlet.HandlerMapping]: Factory method 'resourceHandlerMapping' threw exception; nested exception is java.lang.IllegalStateException: No ServletContext set
	at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:627)
	at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:456)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1288)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1127)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:538)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:498)
	at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:320)
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:318)
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:846)
	at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:863)
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:546)
	at org.springframework.test.context.support.AbstractGenericContextLoader.loadContext(AbstractGenericContextLoader.java:128)
	at org.springframework.test.context.support.AbstractGenericContextLoader.loadContext(AbstractGenericContextLoader.java:60)
	at org.springframework.test.context.support.AbstractDelegatingSmartContextLoader.delegateLoading(AbstractDelegatingSmartContextLoader.java:275)
	at org.springframework.test.context.support.AbstractDelegatingSmartContextLoader.loadContext(AbstractDelegatingSmartContextLoader.java:243)
	at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContextInternal(DefaultCacheAwareContextLoaderDelegate.java:99)
	at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:117)
	... 53 common frames omitted
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.web.servlet.HandlerMapping]: Factory method 'resourceHandlerMapping' threw exception; nested exception is java.lang.IllegalStateException: No ServletContext set
	at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:185)
	at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:622)
	... 71 common frames omitted
Caused by: java.lang.IllegalStateException: No ServletContext set
	at org.springframework.util.Assert.state(Assert.java:73)
	at org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport.resourceHandlerMapping(WebMvcConfigurationSupport.java:486)
	at org.springframework.web.servlet.config.annotation.DelegatingWebMvcConfiguration$$EnhancerBySpringCGLIB$$978e5784.CGLIB$resourceHandlerMapping$30(<generated>)
	at org.springframework.web.servlet.config.annotation.DelegatingWebMvcConfiguration$$EnhancerBySpringCGLIB$$978e5784$$FastClassBySpringCGLIB$$8a3d6c11.invoke(<generated>)
	at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:244)
	at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:363)
	at org.springframework.web.servlet.config.annotation.DelegatingWebMvcConfiguration$$EnhancerBySpringCGLIB$$978e5784.resourceHandlerMapping(<generated>)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154)
	... 72 common frames omitted
```