Spring MVC 控制器测试失败，主体为空

Question

我正在编写带有 spring 引导的小型 REST API 并尝试编写 MVC 测试。
不幸的是，当我从控制器收到空响应时，MVC 测试失败了。

控制器class:

@RestController
@RequestMapping("/test")
public class TestController {

    @GetMapping
    public ResponseEntity getMessage(){
        ResponseEntity responseEntity = null;
        try {
            responseEntity = new ResponseEntity("Hello from: " + InetAddress.getLocalHost().getHostAddress(), HttpStatus.OK);
        } catch (UnknownHostException e) {
            e.printStackTrace();
        }
        return responseEntity;
    }
}

MVC测试方法：

public void shouldReturnDefaultMessage() throws Exception {
    this.mockMvc.perform(get("/test")).andDo(print()).andExpect(status().isOk())
            .andExpect(content().string(containsString("Hello from:")));
}

问题是我 content() 总是空的。
我尝试打印如下响应

MvcResult result = this.mockMvc.perform(get("/test")).andReturn();
String res = result.getResponse().getContentAsString();

这清楚地表明 res 是空的。
我还有一个 mockito 测试，它与正确的响应完美结合。
Mockito 测试：

@Test
public void greetingShouldReturnMessageFromService() throws Exception {
    when(service.getMessage()).thenReturn(ResponseEntity.ok("Hello from:"));
}

MVC 测试的输出：

MockHttpServletRequest:
      HTTP Method = GET
      Request URI = /test
       Parameters = {}
          Headers = []
             Body = null
    Session Attrs = {}

Handler:
             Type = com.test.rest.controller.TestController$MockitoMock5340695
           Method = com.test.rest.controller.TestController$MockitoMock5340695#getMessage()

Async:
    Async started = false
     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 = []

MockHttpServletRequest:
      HTTP Method = GET
      Request URI = /test
       Parameters = {}
          Headers = []
             Body = null
    Session Attrs = {}

Handler:
             Type = com.test.rest.controller.TestController$MockitoMock5340695
           Method = com.test.rest.controller.TestController$MockitoMock5340695#getMessage()

Async:
    Async started = false
     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 = []

MockHttpServletRequest:
      HTTP Method = GET
      Request URI = /test
       Parameters = {}
          Headers = []
             Body = null
    Session Attrs = {}

Handler:
             Type = com.test.rest.controller.TestController$MockitoMock5340695
           Method = com.test.rest.controller.TestController$MockitoMock5340695#getMessage()

Async:
    Async started = false
     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 = []


java.lang.AssertionError: Response content
Expected: a string containing "Hello from:"
     but: was ""
Expected :a string containing "Hello from:"
Actual   :""
<Click to see difference>


    at org.hamcrest.MatcherAssert.assertThat(MatcherAssert.java:18)
    at org.springframework.test.web.servlet.result.ContentResultMatchers.lambda$string(ContentResultMatchers.java:129)
    at org.springframework.test.web.servlet.MockMvc.andExpect(MockMvc.java:196)
    at com.test.rest.TestControllerMockTest.shouldReturnDefaultMessage(TestControllerMockTest.java:38)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:566)
    at org.junit.platform.commons.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:675)
    at org.junit.jupiter.engine.execution.MethodInvocation.proceed(MethodInvocation.java:60)
    at org.junit.jupiter.engine.execution.InvocationInterceptorChain$ValidatingInvocation.proceed(InvocationInterceptorChain.java:125)
    at org.junit.jupiter.engine.extension.TimeoutExtension.intercept(TimeoutExtension.java:132)
    at org.junit.jupiter.engine.extension.TimeoutExtension.interceptTestableMethod(TimeoutExtension.java:124)
    at org.junit.jupiter.engine.extension.TimeoutExtension.interceptTestMethod(TimeoutExtension.java:74)
    at org.junit.jupiter.engine.execution.ExecutableInvoker$ReflectiveInterceptorCall.lambda$ofVoidMethod[=15=](ExecutableInvoker.java:115)
    at org.junit.jupiter.engine.execution.ExecutableInvoker.lambda$invoke[=15=](ExecutableInvoker.java:105)
    at org.junit.jupiter.engine.execution.InvocationInterceptorChain$InterceptedInvocation.proceed(InvocationInterceptorChain.java:104)
    at org.junit.jupiter.engine.execution.InvocationInterceptorChain.proceed(InvocationInterceptorChain.java:62)
    at org.junit.jupiter.engine.execution.InvocationInterceptorChain.chainAndInvoke(InvocationInterceptorChain.java:43)
    at org.junit.jupiter.engine.execution.InvocationInterceptorChain.invoke(InvocationInterceptorChain.java:35)
    at org.junit.jupiter.engine.execution.ExecutableInvoker.invoke(ExecutableInvoker.java:104)
    at org.junit.jupiter.engine.execution.ExecutableInvoker.invoke(ExecutableInvoker.java:98)
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.lambda$invokeTestMethod(TestMethodTestDescriptor.java:202)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.invokeTestMethod(TestMethodTestDescriptor.java:198)
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:135)
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:69)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively(NodeTestTask.java:135)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively(NodeTestTask.java:125)
    at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:135)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively(NodeTestTask.java:123)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:122)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:80)
    at java.base/java.util.ArrayList.forEach(ArrayList.java:1541)
    at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:38)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively(NodeTestTask.java:139)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively(NodeTestTask.java:125)
    at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:135)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively(NodeTestTask.java:123)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:122)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:80)
    at java.base/java.util.ArrayList.forEach(ArrayList.java:1541)
    at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:38)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively(NodeTestTask.java:139)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively(NodeTestTask.java:125)
    at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:135)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively(NodeTestTask.java:123)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:122)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:80)
    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:229)
    at org.junit.platform.launcher.core.DefaultLauncher.lambda$execute(DefaultLauncher.java:197)
    at org.junit.platform.launcher.core.DefaultLauncher.withInterceptedStreams(DefaultLauncher.java:211)
    at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:191)
    at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:128)
    at com.intellij.junit5.JUnit5IdeaTestRunner.startRunnerWithArgs(JUnit5IdeaTestRunner.java:71)
    at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33)
    at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:220)
    at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:53)

Answer 1

你在方法级别尝试过@RequestMapping吗？

示例：

@RequestMapping("/hello") //Changed here
public ResponseEntity getMessage(){
    ResponseEntity responseEntity = null;
    try {
        responseEntity = new ResponseEntity("Hello from: " + InetAddress.getLocalHost().getHostAddress(), HttpStatus.OK);
    } catch (UnknownHostException e) {
        e.printStackTrace();
    }
    return responseEntity;
}

您需要将您现在访问的 url 更改为“/test/hello”。

Answer 2

我不确定，但是按照下面的方法修改后它起作用了。

@Test
    public void shouldReturnDefaultMessage() throws Exception {
        when(service.getMessage()).thenReturn(ResponseEntity.ok("Hello from:")); // Added this line
        this.mockMvc.perform(get("/test")).andDo(print()).andExpect(status().isOk())
                .andExpect(content().string(containsString("Hello from:")));
    }

在上面的方法中，我添加了when(service.getMessage()).thenReturn(ResponseEntity.ok("Hello from:"));行，测试通过。

参考：https://spring.io/guides/gs/testing-web/
在本页末尾声明：

We use @MockBean to create and inject a mock for the GreetingService (if you do not do so, the application context cannot start), and we set its expectations using Mockito

.

Spring MVC 控制器测试失败，主体为空

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