Unit testing code in catch block of a Spring Controller

Question

I have controller with the following structure:

@RequestMapping(value = "${foo.controller.requestMappingUrl.login}", method = RequestMethod.POST)
    public ResponseMessage<String> loginUser(
            @RequestParam("username") String username, HttpServletRequest httpServletRequest,
            HttpServletResponse httpServletResponse) {

    try {

       return fooService.login(username); // can mock test

    } catch (UserNotFoundException e) {
            //CANNOT MOCK TEST THIS BLOCK
            String errorMsg = LoggerUtil.printStackTrace(e);
            LOG.error("[RequestId: {}] UserNotFoundException: {}, Stack: {}", requestId, e.getMessage(), errorMsg);
            httpServletResponse.setStatus(HttpStatus.NOT_ACCEPTABLE.value());
            statusCode = StatusCode.UserNotFound.value();
            responseMessage.buildResponseMessage(StringUtils.EMPTY, HttpStatus.NOT_ACCEPTABLE, statusCode,
                    messageByLocaleService.getMessageResponse(statusCode, null, locale));
    }
}

When I mock to throw the exception UserNotFoundException, I get only NestedServletException. Even though I tried adding expected = NestedServletException.class. The corbetura reports indicate that the code block is not covered in testing. Do you have any suggestion to help test the code inside the catch block.

The test code as requested:

@SuppressWarnings("unchecked")
@Test(expected = UserNotFoundException.class)
    public void testControllerUserNotFoundException() throws Exception {
        Response resp = new Response();
        resp.setStatusCode(StatusCode.UserNotFoundErrorCode);
        when(fooService.login(any(String.class)).thenThrow(UserNotFoundException.class);

        mockMvc.perform(post("/service-user/1.0/auth/login?&username=test")
                        .contentType(contentType)).andExpect(status().isNotAcceptable())
                .andExpect(jsonPath("$.statusCode", is("ERRORCODE144")));

    }

And the stack trace

java.lang.Exception: Unexpected exception, expected but was at org.junit.internal.runners.statements.ExpectException.evaluate(ExpectException.java:28) at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26) at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:75) at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:86) at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:84) at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:252) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:94) 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$2.evaluate(ParentRunner.java:268) at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61) at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70) at org.junit.runners.ParentRunner.run(ParentRunner.java:363) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:191) at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50) at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197) Caused by: org.springframework.web.util.NestedServletException: Request processing failed; nested exception is com.atlassian.crowd.exception.runtime.UserNotFoundException at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:982) at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:872) at javax.servlet.http.HttpServlet.service(HttpServlet.java:648) at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846) at org.springframework.test.web.servlet.TestDispatcherServlet.service(TestDispatcherServlet.java:65) at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) at org.springframework.mock.web.MockFilterChain$ServletFilterProxy.doFilter(MockFilterChain.java:167) at org.springframework.mock.web.MockFilterChain.doFilter(MockFilterChain.java:134) at org.springframework.test.web.servlet.MockMvc.perform(MockMvc.java:155) at id.co.allianz.microservice.cop.app.auth.controller.AuthControllerTest.testControllerUserNotFoundException(AuthControllerTest.java:105) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50) at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12) at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47) at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17) at org.junit.internal.runners.statements.ExpectException.evaluate(ExpectException.java:19) ... 22 more Caused by: com.atlassian.crowd.exception.runtime.UserNotFoundException

Answer 1

You can't expect UserNotFoundException exception out of the controller method because you are suppressing it by simply logging and returning the response with ERRORCODE144.

The best practice here is to configure the ControllerAdvice so that all of the exceptions can be handled globally and your controller looks clean as shown below, I suggest you also look here on spring controllers exception handling.

ExceptionControllerAdvice class:

@ControllerAdvice
public class ExceptionControllerAdvice {

    @ExceptionHandler(UserNotFoundException.class)
    public ResponseEntity<String> handleUnexpectedException(UnexpectedException 
                     unExpectedExe) {

        //log and send the response back to the client here
    }
}

Controller method:

@RequestMapping(value = "${foo.controller.requestMappingUrl.login}",
                                 method = RequestMethod.POST)
public ResponseMessage<String> loginUser(
            @RequestParam("username") String username,
               HttpServletRequest httpServletRequest,
               HttpServletResponse httpServletResponse) {

       return fooService.login(username);
}

JUnit setup & test methods:

@Before
    public void setUp() throws Exception {
        MockitoAnnotations.initMocks(this);
    mockMvc = MockMvcBuilders.standaloneSetup(projectController)
                .setMessageConverters(new MappingJackson2HttpMessageConverter())
                .setControllerAdvice(new ExceptionControllerAdvice()).build();
}


@SuppressWarnings("unchecked")
@Test
    public void testControllerUserNotFoundException() throws Exception {
        Response resp = new Response();
        resp.setStatusCode(StatusCode.UserNotFoundErrorCode);
        when(fooService.login(any(String.class)).
        thenThrow(UserNotFoundException.class);
        mockMvc.perform(post("/service-user/1.0/auth/login?&username=test")
                        .contentType(contentType)).
     andExpect(status().isNotAcceptable())
                .andExpect(jsonPath("$.statusCode", is("ERRORCODE144")));
}