DeferredResult 的 Spring MVC 单元测试不调用超时回调

Question

我在 Java 7 上使用 Spring 4.3.18 和 Spring Boot 1.5.14。

我正在实现一个 RestController 端点，它返回DeferredResult带有超时回调的 a 。我正在尝试为超时回调编写单元测试，但无法获得MockMvc调用超时回调的单元测试。

为了测试的目的，我写了这个端点：

@PostMapping("/test")
public DeferredResult<String>
testit() {
    logger.info("testit called");
    final DeferredResult<String> rv = new DeferredResult<>(1000L);
    rv.onTimeout(new Runnable() {
        @Override
        public void run() {
            logger.info("run called");
            rv.setResult("timed out");
        }
    });
    return rv;
}

和这个单元测试：

@Autowired
private MockMvc mockMvc;

@Test
public void testTest() throws Exception {
    MvcResult result = mockMvc.perform(post("/rest/tasks/test"))
        .andExpect(request().asyncStarted())
        .andReturn();
    result.getAsyncResult(1500);
    mockMvc.perform(asyncDispatch(result))
        .andExpect(status().isOk())
        ;
}

（调用result.getAsyncResult(1500)基于https://jira.spring.io/browse/SPR-16869）

当我运行此命令时，testit()端点被调用，在 1500 毫秒的延迟后，我收到一个异常，抱怨setResult()从未被调用。未调用超时处理程序：

java.lang.IllegalStateException: Async result for handler [public org.springframework.web.context.request.async.DeferredResult<java.lang.String> my.package.TasksController.testit()] was not set during the specified timeToWait=1500
    at org.springframework.test.web.servlet.DefaultMvcResult.getAsyncResult(DefaultMvcResult.java:135)
    at my.package.TasksControllerTest.testTest(TasksControllerTest.java:200)

2517 [main] INFO my.package.TasksController - testit called

MockHttpServletRequest:
      HTTP Method = POST
      Request URI = /rest/tasks/test
       Parameters = {}
          Headers = {}

Handler:
             Type = my.package.TasksController
           Method = public org.springframework.web.context.request.async.DeferredResult<java.lang.String> my.package.TasksController.testit()

Async:
    Async started = true
     Async result = null

Resolved Exception:
             Type = null

ModelAndView:
        View name = null
             View = null
            Model = null

FlashMap:
       Attributes = null

MockHttpServletResponse:
           Status = 200
    Error message = null
          Headers = {}
     Content type = null
             Body = 
    Forwarded URL = null
   Redirected URL = null
          Cookies = []
4037 [Thread-2] INFO org.springframework.web.context.support.GenericWebApplicationContext - Closing org.springframework.web.context.support.GenericWebApplicationContext@6ea91f6: startup date [Thu Jul 26 19:44:31 EDT 2018]; root of context hierarchy

我需要做什么才能使测试框架调用 DeferredResult 上的超时处理程序？

Answer 1

似乎可以在单元测试中创建一个合成超时，如下所示：

@Test
public void testTest() throws Exception {
    MvcResult result = mockMvc.perform(post("/rest/tasks/test"))
        .andExpect(request().asyncStarted())
        .andReturn();
    // Trigger a timeout on the request
    MockAsyncContext ctx = (MockAsyncContext) result.getRequest().getAsyncContext();
    for (AsyncListener listener : ctx.getListeners()) {
        listener.onTimeout(null);
    }
    mockMvc.perform(asyncDispatch(result))
        .andExpect(status().isOk())
        ;
}

访问请求的异步侦听器并调用onTimeout()将导致调用DeferredRequest的超时回调。

对于这个测试来说，我的问题的调用result.getAsyncResult(1500)是多余的，因为无论如何asyncDispatch()都会调用getAsyncResult()。