使用 Spring、MongoDB 使用 ObjectId 测试 REST 端点

Question

我是 MongoDB 新手，正在为 Mongo 支持的 REST Web 服务编写一系列单元测试。这是 /clients/{id} enpoint 的简单测试：

@RunWith(MockitoJUnitRunner.class)
public class ClientsControllerMockMvcStandaloneTest {

    private MockMvc mvc;

    @Mock
    private ClientsRepository clientsRepository;

    @Mock
    private ModelMapper modelMapper;

    @InjectMocks
    private ClientsController clientsController;

    private ExceptionHandlerExceptionResolver createExceptionResolver() {

        ExceptionHandlerExceptionResolver exceptionResolver = new ExceptionHandlerExceptionResolver() {

            @SuppressWarnings("ConstantConditions")
            @Override
            protected ServletInvocableHandlerMethod getExceptionHandlerMethod(final HandlerMethod handlerMethod,
                                                                              final Exception exception) {

                final Method method = new ExceptionHandlerMethodResolver(RestResponseEntityExceptionHandler.class)
                        .resolveMethod(exception);

                final RestResponseEntityExceptionHandler handler = new RestResponseEntityExceptionHandler();

                return new ServletInvocableHandlerMethod(handler, method);
            }
        };

        exceptionResolver.getMessageConverters().add(new MappingJackson2HttpMessageConverter());
        exceptionResolver.afterPropertiesSet();

        return exceptionResolver;
    }

    @Before
    public void setup() {

        JacksonTester.initFields(this, new ObjectMapper());

        mvc = MockMvcBuilders.standaloneSetup(clientsController)
                .setHandlerExceptionResolvers(createExceptionResolver())
                .build();
    }

    // GET /api/clients/{id} 200

    @Test
    public void findById_ClientEntryFound_ShouldReturnFoundClientEntry() throws Exception {

        final ObjectId id = new ObjectId();

        final Client client = Client.builder()
                .id(id)
                .name("Microsoft")
                .build();

        final ClientDTO clientDTO = ClientDTO.builder()
                .id(id)
                .name("Microsoft")
                .build();

        when(clientsRepository.findById(id))
                .thenReturn(Optional.of(client));

        when(modelMapper.map(client, ClientDTO.class))
                .thenReturn(clientDTO);

        mvc.perform(get("/clients/" + id.toString())
                .accept(TestUtils.APPLICATION_JSON_UTF8))
                .andExpect(content().contentType(TestUtils.APPLICATION_JSON_UTF8))
                .andExpect(status().isOk())
                .andExpect(jsonPath("$.id", is(id)))
                .andExpect(jsonPath("$.name", is("Microsoft")))
                .andDo(MockMvcResultHandlers.print());

        verify(modelMapper, times(1)).map(client, ClientDTO.class);
        verify(clientsRepository, times(1)).findById(id);

        verifyNoMoreInteractions(clientsRepository);
    }
}

我希望这能起作用，但我得到以下结果：

java.lang.AssertionError: JSON path "$.id"
Expected: is <5c9b9a0289d2b311b150b92c>
     but: was <{timestamp=1553701378, machineIdentifier=9032371, processIdentifier=4529, counter=5290284, timeSecond=1553701378, time=1553701378000, date=1553701378000}>
Expected :is <5c9b9a0289d2b311b150b92c>
Actual   :<{timestamp=1553701378, machineIdentifier=9032371, processIdentifier=4529, counter=5290284, timeSecond=1553701378, time=1553701378000, date=1553701378000}>
 <Click to see difference>

任何帮助将不胜感激（包括任何指示，如果您认为我的一般方法可以改进！）。

干杯!

Answer 1

杰克逊不知道您的ObjectId实例应该序列化为5c9b9a0289d2b311b150b92c而不是：

{
  "timestamp": 1553701378,
  "machineIdentifier": 9032371,
  "processIdentifier": 4529,
  "counter": 5290284,
  "time": 1553701378000,
  "date": 1553701378000,
  "timeSecond": 1553701378
}

幸运的是，它很容易修复。该ObjectId#toString()方法（将在内部调用ObjectId#toHexString()）允许您将实例转换ObjectId为 24 字节的十六进制字符串表示形式。

因此，您可以使用@JsonSerializewithToStringSerializer将ObjectId实例表示为字符串：

{
  "timestamp": 1553701378,
  "machineIdentifier": 9032371,
  "processIdentifier": 4529,
  "counter": 5290284,
  "time": 1553701378000,
  "date": 1553701378000,
  "timeSecond": 1553701378
}

然后，在您的测试中，使用ObjectId#toString()方法（或ObjectId#toHexString()）进行断言：

@JsonSerialize(using = ToStringSerializer.class)
private ObjectId id;

或者，假设您使用的是 Spring Data for MongoDB，而不是ObjectId，您可以使用：

.andExpect(jsonPath("$.id", is(id.toString())))

您还可以在映射器层中处理ObjectId到的转换。String