@WebAppConfiguration fails with ServletServerContainerFactoryBean in the ApplicationContext [SPR-14367]

[spring-projects-issues]

Craig opened SPR-14367 and commented

The servlet container used by unit tests doesn't support websockets.

To see this issue, define this configuration class (as documented at http://docs.spring.io/spring/docs/current/spring-framework-reference/html/websocket.html#websocket-server-runtime-configuration )

@Configuration
@EnableWebSocket
public class WebSocketConfig {

	private static final int MAX_MESSAGE_SIZE = 16 * 1024 * 1024;

	@Bean
	public ServletServerContainerFactoryBean createWebSocketContainer() {
		ServletServerContainerFactoryBean container = new ServletServerContainerFactoryBean();
		container.setMaxTextMessageBufferSize(MAX_MESSAGE_SIZE);
		container.setMaxBinaryMessageBufferSize(MAX_MESSAGE_SIZE);
		return container;
	}
}

then run this unit test (which is created by the Spring boot web application archetype):

@RunWith(SpringJUnit4ClassRunner.class)
@SpringApplicationConfiguration(classes = ExampleApplication.class)
@WebAppConfiguration
public class ExampleApplicationTests {

	@Test
	public void contextLoads() {
	}

}

The result is that the test fails with this stack trace:

Caused by: java.lang.IllegalStateException: A ServletContext is required to access the javax.websocket.server.ServerContainer instance
	at org.springframework.util.Assert.state(Assert.java:392)
	at org.springframework.web.socket.server.standard.ServletServerContainerFactoryBean.afterPropertiesSet(ServletServerContainerFactoryBean.java:99)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1637)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1574)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:545)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482)
	at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306)
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302)
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:753)
	at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:839)
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:538)
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:766)
	at org.springframework.boot.SpringApplication.createAndRefreshContext(SpringApplication.java:361)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:307)
	at org.springframework.boot.test.SpringApplicationContextLoader.loadContext(SpringApplicationContextLoader.java:98)
	at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContextInternal(DefaultCacheAwareContextLoaderDelegate.java:98)
	at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:116)
	at org.springframework.test.context.support.DefaultTestContext.getApplicationContext(DefaultTestContext.java:83)
	at org.springframework.test.context.web.ServletTestExecutionListener.setUpRequestContextIfNecessary(ServletTestExecutionListener.java:183)
	at org.springframework.test.context.web.ServletTestExecutionListener.prepareTestInstance(ServletTestExecutionListener.java:123)
	at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:228)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest(SpringJUnit4ClassRunner.java:230)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner$1.runReflectiveCall(SpringJUnit4ClassRunner.java:289)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.methodBlock(SpringJUnit4ClassRunner.java:291)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:249)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:89)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
	at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
	at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:193)
	at org.apache.maven.surefire.junit4.JUnit4Provider.execute(JUnit4Provider.java:283)
	at org.apache.maven.surefire.junit4.JUnit4Provider.executeWithRerun(JUnit4Provider.java:173)
	at org.apache.maven.surefire.junit4.JUnit4Provider.executeTestSet(JUnit4Provider.java:153)
	at org.apache.maven.surefire.junit4.JUnit4Provider.invoke(JUnit4Provider.java:128)
	at org.apache.maven.surefire.booter.ForkedBooter.invokeProviderInSameClassLoader(ForkedBooter.java:203)
	at org.apache.maven.surefire.booter.ForkedBooter.runSuitesInProcess(ForkedBooter.java:155)
	at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:103)

The problem is that the org.springframework.mock.web.MockServletContext instance (referenced in the stack trace frame "org.springframework.web.socket.server.standard.ServletServerContainerFactoryBean.afterPropertiesSet(ServletServerContainerFactoryBean.java:99)") doesn't have the servlet attribute "javax.websocket.server.ServerContainer" set to an instance of javax.websocket.server.ServerContainer (the attribute is instead set to null).

As a workaround, the test class can be annotated with:

@org.springframework.boot.test.IntegrationTest("server.port:0")

causing a real servlet context (which does support websockets) to be used instead of a mock one.

---

Affects: 4.2.6

[spring-projects-issues]

Rossen Stoyanchev commented

The Spring TestContext framework support and the @WebAppConfiguration annotation is container-less testing by definition. Essentially the mock request and response, not an actual Servlet container. Were you expecting an actual ServerContainer or some mock version that would simply prevent your configuration from failing to load?

[spring-projects-issues]

Craig commented

I wouldn't expect it to provide a real ServerContainer because, as you said, that would require a full servlet container to be running. I would expect it to return a mock that provides the necessary features to perform unit testing. There is precedent for such mocks; for example, MockServletContext already includes use of MockSessionCookieConfig and MockRequestDispatcher.

It was pretty surprising to me that using code given in the Spring docs causes a unit test provided by default with new Spring projects to fail :)

[spring-projects-issues]

Rossen Stoyanchev commented

Certainly we need to make sure the above configuration at least doesn't fail. I'm still not sure what else makes sense beyond that.

For example we could insert a package private, empty stub (no-op) implementation of ServerContainer as the request attribute. That will allow the above configuration to load but calls to the ServerContainer would be ignored. I see no way meaningful way to implement the connectToServer methods in a mock scenario as we can't actually connect. As for the addEndpoint methods there is not much to do there either. For once Spring's own WebSocket support does not rely on such registrations and uses a RequestUpgradeStrategy for each server. For straight-up JSR-356 Endpoint implementations, such as the ones that would be registered by the factory bean, there is nothing we can do outside a container.

I see this strictly as a request to ensure configuration such as the above does not fail and prevent tests from running.

[spring-projects-issues]

Rossen Stoyanchev commented

Updated title (was: "Unit testing servlet container should support websockets").

[spring-projects-issues]

Sam Brannen commented

Resolved as described in GitHub commit f7dd757:

Support WebSocket ServletServerContainerFB in the TCF

Prior to this commit, any attempt to include a bean of type
ServletServerContainerFactoryBean in the WebApplicationContext for an
integration test class annotated with @WebAppConfiguration in
conjunction the Spring TestContext Framework (TCF) would have resulted
in an IllegalStateException stating that "A ServletContext is required
to access the javax.websocket.server.ServerContainer instance."

In such scenarios, the MockServletContext was in fact present in the
WebApplicationContext; however there was no WebSocket ServerContainer
stored in the ServletContext.

This commit addresses this issue by introducing the following.

• MockServerContainer: a private mock implementation of the
  javax.websocket.server.ServerContainer interface.

• MockServerContainerContextCustomizer: a ContextCustomizer that
  instantiates a new MockServerContainer and stores it in the
  ServletContext under the attribute named
  "javax.websocket.server.ServerContainer".

• MockServerContainerContextCustomizerFactory: a
  ContextCustomizerFactory which creates a
  MockServerContainerContextCustomizer if WebSocket support is present
  in the classpath and the test class is annotated with
  @WebAppConfiguration. This factory is registered by default via the
  spring.factories mechanism.

[spring-projects-issues]

xiaokun commented

This error still occurs in version 4.3.3 in spring mvc project.

[spring-projects-issues]

xiaokun commented

Here are test code:

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration({ "classpath*:applicationContext*.xml" })
public class Test{

}

Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'createWebSocketContainer' defined in net.ebaolife.tpa.websocket.WebSocketConfig: Invocation of init method failed; nested exception is java.lang.IllegalStateException: A ServletContext is required to access the javax.websocket.server.ServerContainer instance
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1583)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:545)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482)
	at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306)
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302)
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:732)
	at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:861)
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:541)
	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:108)
	at org.springframework.test.context.support.AbstractDelegatingSmartContextLoader.loadContext(AbstractDelegatingSmartContextLoader.java:251)
	at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContextInternal(DefaultCacheAwareContextLoaderDelegate.java:98)
	at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:116)
	... 24 more
Caused by: java.lang.IllegalStateException: A ServletContext is required to access the javax.websocket.server.ServerContainer instance
	at org.springframework.util.Assert.state(Assert.java:392)
	at org.springframework.web.socket.server.standard.ServletServerContainerFactoryBean.afterPropertiesSet(ServletServerContainerFactoryBean.java:102)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1642)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1579)
	... 39 more

[spring-projects-issues]

xiaokun commented

In test class, add @WebAppConfiguration, this error is gone.

[spring-projects-issues]

Rossen Stoyanchev commented

Once the fix version is released, the ticket is permanently closed. If you're still having an issue you need to open a new ticket with the relevant version and a fresh description.