model 映射器模拟在 Z2A2D595E6ED9A0B24F027F2B63B134D 引导单元中返回 null object

Question

I am trying to write unit tests for a rest controller class in my application using MockMvc and Mockito.I have DTO class for my entity class which I give as input for the controller method. The controller method maps this DTO object into the entity class and persists it using my service class. After persisting, a new DTO class is created by mapping the object returned by the service class' method and this DTO is returned in the ResponseEntity object. In my unit test, I have mocked the service class and the ModelMapper class using @MockBean annotation. I am also setting the expected return values for the methods of the mocked class. But when I run the test, I see that the response body is empty, which I assume is because the mock mapper is not returning the DTO object correctly. Can someone please help me to make the mock mapper return the object correctly so that my tests pass? Thanks.

Here's the controller code:

@RequestMapping(value = "", method=RequestMethod.POST)
    public ResponseEntity<BranchDto> addBranch(@RequestBody BranchDto branchDto) {
        Branch branch = modelMapper.map(branchDto, Branch.class);
        Branch addedBranch = branchService.addBranch(branch);
        return new ResponseEntity<>(modelMapper.map(addedBranch, BranchDto.class), HttpStatus.CREATED);
    }

Here's the unit test code:

    @Autowired
    private MockMvc mockMvc;

    @MockBean
    private BranchService branchService;

    @MockBean
    private ModelMapper mockModelMapper;

    @Test
    public void testAddBranch() throws Exception{
        BranchDto mockBranchDtoToAdd = new BranchDto();
        mockBranchDtoToAdd.setBranchName("TestBranch");
        mockBranchDtoToAdd.setContactNumber("12345");
        mockBranchDtoToAdd.setEmailId("test@abc.com");
        mockBranchDtoToAdd.setCity("TestCity");
        Branch mockBranchToAdd = new Branch();
        mockBranchToAdd.setBranchName("TestBranch");
        mockBranchToAdd.setContactNumber("12345");
        mockBranchToAdd.setEmailId("test@abc.com");
        mockBranchToAdd.setCity("TestCity");

        Branch mockAddedBranch = new Branch();
        mockAddedBranch.setBranchName("TestBranch");
        BranchDto mockAddedBranchDto = new BranchDto();
        mockAddedBranchDto.setBranchName("TestBranch");
        mockAddedBranchDto.setContactNumber("12345");
        mockAddedBranchDto.setEmailId("test@abc.com");
        mockAddedBranchDto.setCity("TestCity");

        Mockito.when(mockModelMapper.map(mockBranchDtoToAdd, Branch.class)).thenReturn(mockBranchToAdd);
        Mockito.when(branchService.addBranch(mockBranchToAdd)).thenReturn(mockAddedBranch);
        Mockito.when(mockModelMapper.map(mockAddedBranch, BranchDto.class)).thenReturn(mockAddedBranchDto);


        ObjectMapper mapper = new ObjectMapper();
        String mockBranchDtoToAddStr = mapper.writeValueAsString(mockBranchDtoToAdd);
        System.out.println(mockBranchDtoToAddStr);
        mockMvc.perform(post("/branches").contentType(MediaType.APPLICATION_JSON).content(mockBranchDtoToAddStr))
        .andExpect(MockMvcResultMatchers.status().isCreated())
        .andExpect(MockMvcResultMatchers.jsonPath("$.branchName").value("TestBranch"));
    }

Answer 1

After a lot of digging, I figured that the line

Mockito.when(branchService.addBranch(mockBranchToAdd)).thenReturn(mockAddedBranch);

was not setting the mock object correctly. I changed this line to use any() in the when() method and it worked fine thereafter. Here's the updated code:

Mockito.when(branchService.addBranch(org.mockito.ArgumentMatchers.any())).thenReturn(mockAddedBranch);
Mockito.when(mockModelMapper.map(org.mockito.ArgumentMatchers.any(), org.mockito.ArgumentMatchers.any())).thenReturn(mockAddedBranch);