spring test集成resteasy mock单元测试

  mock框架在web项目中进行单元测试非常方便，resteasy作为一个优秀的rest框架，也为我们提供了mock测试工具，但是并没有替我们集成spring，因此我们编写的Resource类无法完成bean的注入，进行单元测试时比较麻烦。我们希望像springmvc那样非常方便地进行单元测试(http://blog.csdn.net/dwade_mia/article/details/77451605)，为了解决该问题，笔者扩展了spring test的代码，完成spring test与resteasy mock的集成。

spring test源码解读

SpringJUnit4ClassRunner

SpringJUnit4ClassRunner集成junit测试入口
TestContextManager由SpringJUnit4ClassRunner创建，负责创建TestContext上下文

下面是一个常用的Mock测试类

@WebAppConfiguration(value="src/main/webapp")@ContextConfiguration( locations={"classpath*:spring-config/applicationContext.xml"} )@RunWith( SpringJUnit4ClassRunner.class )public class BaseApiTest extends AbstractJUnit4SpringContextTests {       // ......}

其中RunWith指定SpringJUnit4ClassRunner，而SpringJUnit4ClassRunner重写了createTest方法，在junit启动的时候，会调用createTest方法，包括创建Spring容器，对Test测试类进行属性注入等，下图是方法调用的关系图

SpringJunit4ClassRunner.java    //初始化的时候会创建TestContextManager，用于获取测试基类的信息，比如注解等，由TestContextManager创建    public SpringJUnit4ClassRunner(Class<?> clazz) throws InitializationError {        super(clazz);        if (logger.isDebugEnabled()) {            logger.debug("SpringJUnit4ClassRunner constructor called with [" + clazz + "]");        }        ensureSpringRulesAreNotPresent(clazz);        this.testContextManager = createTestContextManager(clazz);    }    protected TestContextManager createTestContextManager(Class<?> clazz) {        return new TestContextManager(clazz);    }    //重写junit实例化对象的方法    protected Object createTest() throws Exception {        Object testInstance = super.createTest();        getTestContextManager().prepareTestInstance(testInstance);        return testInstance;    }

TestExecutionListener

以下是spring自带的TestExecutionListener，比如测试类的属性注入，其中DependencyInjectionTestExecutionListener用于对测试类进行注入属性注入，当然我们也可以在测试类上面添加自定义的监听器

在创建测试类实例的时候，需要对测试类进行处理，最终调用TextContextManager的prepareTestInstance方法执行监听器的处理操作，默认包括ServletTestExecutionListener, DirtiesContextBeforeModesTestExecutionListener, DependencyInjectionTestExecutionListener, DirtiesContextTestExecutionListener，如果是继承了AbstractTransactionalJUnit4SpringContextTests的时候，还会添加TransactionTestExecutionListener这个Listener

SpringJunit4ClassRunner.java      protected Object createTest() throws Exception {    Object testInstance = super.createTest();    getTestContextManager().prepareTestInstance(testInstance);    return testInstance;}

TestContextManager.java    @Override    public void prepareTestInstance(TestContext testContext) throws Exception {        setUpRequestContextIfNecessary(testContext);    }    private void setUpRequestContextIfNecessary(TestContext testContext) {        if (!isActivated(testContext) || alreadyPopulatedRequestContextHolder(testContext)) {            return;        }        //获取Spring容器，如果没有的话，由测试类设置的@ContextConfiguration信息创建容器        ApplicationContext context = testContext.getApplicationContext();        if (context instanceof WebApplicationContext) {            WebApplicationContext wac = (WebApplicationContext) context;            ServletContext servletContext = wac.getServletContext();            // other code......            MockServletContext mockServletContext = (MockServletContext) servletContext;            MockHttpServletRequest request = new MockHttpServletRequest(mockServletContext);            request.setAttribute(CREATED_BY_THE_TESTCONTEXT_FRAMEWORK, Boolean.TRUE);            MockHttpServletResponse response = new MockHttpServletResponse();            ServletWebRequest servletWebRequest = new ServletWebRequest(request, response);            RequestContextHolder.setRequestAttributes(servletWebRequest);            testContext.setAttribute(POPULATED_REQUEST_CONTEXT_HOLDER_ATTRIBUTE, Boolean.TRUE);            testContext.setAttribute(RESET_REQUEST_CONTEXT_HOLDER_ATTRIBUTE, Boolean.TRUE);            if (wac instanceof ConfigurableApplicationContext) {                @SuppressWarnings("resource")                ConfigurableApplicationContext configurableApplicationContext = (ConfigurableApplicationContext) wac;                ConfigurableListableBeanFactory bf = configurableApplicationContext.getBeanFactory();                //我们可以在测试类上面注入以下request、response对象                bf.registerResolvableDependency(MockHttpServletResponse.class, response);                bf.registerResolvableDependency(ServletWebRequest.class, servletWebRequest);            }        }    }

下图是一个调用栈，ServerletTestExecutionListner会调用getApplicationContext()，如果当前上下文中没有Spring容器的话，会由cacheAwareContextLoaderDelegate.loadContext(this.mergedContextConfiguration)方法创建Spring容器，如果我们想自己创建Spring容器的话，需要注入一个自定义的cacheAwareContextLoaderDelegate，并重写loadContext方法。

这个CacheAwareContextLoaderDelegate接口默认只有一个实现DefaultCacheAwareContextLoaderDelegate，我们看下调用逻辑，原来默认是由DefaultTestContext调用的，而DefaultTestContext是由TestContextManager创建的，我们找到TestContextManager


咱们看下这个TestContextManager的注释，如果我们在测试类上面定义了@BootstrapWith，就使用自定义的，否则会使用默认的DefaultTestContextBootstrapper，如果我们使用了@WebAppConfiguration则会使用WebTestContextBootstrapper，跟进BootstrapUtils.resoveTestContextBootstrapper方法便知这个逻辑处理

public TestContextManager(Class<?> testClass) {        this(BootstrapUtils.resolveTestContextBootstrapper(BootstrapUtils.createBootstrapContext(testClass)));    }

BootstrapUtils.javaprivate static Class<?> resolveDefaultTestContextBootstrapper(Class<?> testClass) throws Exception {        ClassLoader classLoader = BootstrapUtils.class.getClassLoader();        AnnotationAttributes attributes = AnnotatedElementUtils.findMergedAnnotationAttributes(testClass,            WEB_APP_CONFIGURATION_ANNOTATION_CLASS_NAME, false, false);        if (attributes != null) {            return ClassUtils.forName(DEFAULT_WEB_TEST_CONTEXT_BOOTSTRAPPER_CLASS_NAME, classLoader);        }        return ClassUtils.forName(DEFAULT_TEST_CONTEXT_BOOTSTRAPPER_CLASS_NAME, classLoader);    }

spring test源码扩展，集成resteasy

首先，看一下TestContextBootstrapper的类图，因为是Web容器，所以我们继承WebTestContextBootstrapper，重写getCacheAwareContextLoaderDelegate()方法，返回我们自定义的CacheAwareContextLoaderDelegate实现类

public class ResteasyTestContextBootstrapper extends WebTestContextBootstrapper {    @Override    protected CacheAwareContextLoaderDelegate getCacheAwareContextLoaderDelegate() {        return new ResteasyCacheAwareContextLoaderDelegate();    }}

/*** 参考AbstractGenericWebContextLoader.loadContext的方法，使用MockServletContext* 创建Listener* @author huangxf* @date 2017年4月30日*/public class ResteasyCacheAwareContextLoaderDelegate extends        DefaultCacheAwareContextLoaderDelegate {    private ServletContext servletContext;    @Override    protected ApplicationContext loadContextInternal(            MergedContextConfiguration mergedConfig)            throws Exception {        if (!(mergedConfig instanceof WebMergedContextConfiguration)) {            throw new IllegalArgumentException(String.format(                "Cannot load WebApplicationContext from non-web merged context configuration %s. "                        + "Consider annotating your test class with @WebAppConfiguration.", mergedConfig));        }        WebMergedContextConfiguration webMergedConfig = (WebMergedContextConfiguration) mergedConfig;        String resourceBasePath = webMergedConfig.getResourceBasePath();        ResourceLoader resourceLoader = resourceBasePath.startsWith(ResourceLoader.CLASSPATH_URL_PREFIX) ? new DefaultResourceLoader()                : new FileSystemResourceLoader();        this.servletContext = new MockServletContext( resourceBasePath, resourceLoader );        StringBuilder locations = new StringBuilder();        for ( String location : webMergedConfig.getLocations() ) {            locations.append( location ).append( "," );        }        locations.deleteCharAt( locations.length() - 1 );        servletContext.setInitParameter( "contextConfigLocation", locations.toString() );        //初始化ServletListener        ServletContextListener bootstrapListener = new SpringResteasyBootstrap();        ServletContextEvent event = new ServletContextEvent( servletContext );        bootstrapListener.contextInitialized( event );        //存放在上下文中        servletContext.setAttribute( SpringResteasyBootstrap.class.getName(), bootstrapListener );        return WebApplicationContextUtils.getWebApplicationContext( servletContext );    }    @Override    public void closeContext(            MergedContextConfiguration mergedContextConfiguration,            HierarchyMode hierarchyMode) {        ServletContextListener listener = (ServletContextListener)servletContext.getAttribute( SpringResteasyBootstrap.class.getName() );        listener.contextDestroyed( new ServletContextEvent( servletContext ) );        super.closeContext(mergedContextConfiguration, hierarchyMode);    }}

于是我们的Test测试类变成这样：

@WebAppConfiguration(value="src/main/webapp")@ContextConfiguration( locations={"classpath*:spring-config/applicationContext.xml"} )@RunWith( SpringJUnit4ClassRunner.class )@BootstrapWith( value=ResteasyTestContextBootstrapper.class )public class BaseResteasyTest extends AbstractJUnit4SpringContextTests {    protected Logger logger = LoggerFactory.getLogger( this.getClass() );    @Resource    protected WebApplicationContext wac;    protected HttpServletDispatcher dispatcher;    @Before    public void beforeTest() throws ServletException {        ServletContext servletContext = wac.getServletContext();        MockServletConfig config = new MockServletConfig( servletContext );        this.dispatcher = new HttpServletDispatcher();        dispatcher.init( config );    }    protected void logResponse( MockHttpResponse response ) {        logger.info( "status:{}", response.getStatus() );        logger.info( "Response content:{}", response.getContentAsString() );    }}

我们由@BootstrapWith指定ResteasyCacheAwareContextLoaderDelegate，由它负责创建相关的ServletListener，由于项目里面集成了Resteasy和Spring，因此创建Resteasy和Spring的监听器，该逻辑与web容器的启动逻辑相同

这样便初始化了Spring和Resteasy的ServletListener，还需要初始化Resteasy的HttpServletDispatcher，我们可以在测试类中可以注入WebapplicationContext，这样便可以获取ServletContext，在@BeforeTest方法中直接new出HttpServletDispatcher实例再调用init方法即可。
那么，如何使用呢？在servlet容器中是根据我们设置的url-pattern去寻找对应的Servlet，从而调用service方法即可，我们也可以用调用HttpServletDispatcher提供的getDispatcher().invoke()方法，只不过是传入的参数不同而已。

public class PaymentApiTest extends BaseResteasyTest {    @Test    public void testPayOff() throws Exception {        GatewayPayOffReq req = new GatewayPayOffReq();        req.setPartnerId( "10000" );        String json = "{\"data\":" + JsonUtils.toJson( req ) + "}";        MockHttpRequest httpRequest = MockHttpRequest.post( "/pay/payoff" )                .contentType( MediaType.APPLICATION_JSON ).accept( MediaType.APPLICATION_JSON )                .content( json.getBytes( "UTF-8" ) );        MockHttpResponse httpResponse = new MockHttpResponse();        //请求        dispatcher.getDispatcher().invoke( httpRequest, httpResponse );        //打印响应结果        logResponse( httpResponse );    }

Springmvc MockMvc

另外，我们再来研究下Spring的MockMvc测试类，看下Spring是怎么做的，最终发现逻辑上是一致的，只不过提供了很多功能。

/*** 使用mock测试web服务* @author huangxf* @date 2017年4月12日*/@WebAppConfiguration(value="src/main/webapp")@ContextConfiguration( locations={"classpath*:spring-config/core/application-consumer.xml",         "classpath*:spring-config/core/springmvc-servlet.xml"} )@RunWith( SpringJUnit4ClassRunner.class )public class BaseControllerTest extends AbstractJUnit4SpringContextTests {    @Resource    protected WebApplicationContext wac;    protected MockMvc mockMvc;    @Before    public void beforeTest() {        mockMvc = MockMvcBuilders.webAppContextSetup( wac ).build();    }}

而在这个里面又调用了父类的createMockMvc方法，在这个里面对TestDispatcherServlet(DispatcherServlet的子类)进行初始化，最终返回持有TestDispatcherServlet、Filter实例的MockMvc对象

MockMvcBuilderSupport.java    protected final MockMvc createMockMvc(Filter[] filters, MockServletConfig servletConfig,            WebApplicationContext webAppContext, RequestBuilder defaultRequestBuilder,            List<ResultMatcher> globalResultMatchers, List<ResultHandler> globalResultHandlers,            List<DispatcherServletCustomizer> dispatcherServletCustomizers) {        ServletContext servletContext = webAppContext.getServletContext();        TestDispatcherServlet dispatcherServlet = new TestDispatcherServlet(webAppContext);        if (dispatcherServletCustomizers != null) {            for (DispatcherServletCustomizer customizers : dispatcherServletCustomizers) {                customizers.customize(dispatcherServlet);            }        }        try {            dispatcherServlet.init(servletConfig);        }        catch (ServletException ex) {            // should never happen..            throw new MockMvcBuildException("Failed to initialize TestDispatcherServlet", ex);        }        //创建对象，并持有TestDispatcherServlet和Filter实例        mockMvc.setDefaultRequest(defaultRequestBuilder);        mockMvc.setGlobalResultMatchers(globalResultMatchers);        mockMvc.setGlobalResultHandlers(globalResultHandlers);        return mockMvc;    }

在我们调用MockMvc的perform方法发起请求时，在这个方法内部会创建FilterChain的Mock实例MockFilterChain，然后挨个调用Filter的doFilter方法，和真实的Servlet容器一样。在MockFilterChain的构造方法里面，会把dispatcherServlet包装成一个Filter，调用最后一个Filter的doFilter方法时，会调用dispatcherServlet的service()方法，这样和web的流程就相同了。

public ResultActions perform(RequestBuilder requestBuilder) throws Exception {        MockHttpServletRequest request = requestBuilder.buildRequest(this.servletContext);        MockHttpServletResponse response = new MockHttpServletResponse();        if (requestBuilder instanceof SmartRequestBuilder) {            request = ((SmartRequestBuilder) requestBuilder).postProcessRequest(request);        }        final MvcResult mvcResult = new DefaultMvcResult(request, response);        request.setAttribute(MVC_RESULT_ATTRIBUTE, mvcResult);        RequestAttributes previousAttributes = RequestContextHolder.getRequestAttributes();        RequestContextHolder.setRequestAttributes(new ServletRequestAttributes(request, response));        //在MockFilterChain的构造方法里面，会把dispatcherServlet包装成一个Filter，调用最后一个Filter的doFilter方法时，会调用dispatcherServlet的service()方法        MockFilterChain filterChain = new MockFilterChain(this.servlet, this.filters);        filterChain.doFilter(request, response);        //......        return new ResultActions() {            //......                    };    }

相关的代码在net.dwade.plugins.resteasy.mock这个包下面，github地址：https://github.com/huangxfchn/dwade/tree/master/framework-plugins