为什么 MockMvc 请求在测试成功时检索空的 responseBody？

Question

我正在尝试测试我的 Spring Boot rest 控制器，以检查在 bean 验证失败时请求是否发送属性错误。

我有一个@RestController:

@RestController
@RequestMapping("/restaurants")
public class RestaurantsApiController {

    private final RestaurantService restaurantService;
    private final ProductRepository productRepository;
    private final ProductMapper productMapper;

    public RestaurantsApiController(RestaurantService restaurantService, ProductRepository productRepository, ProductMapper productMapper) {
        this.restaurantService = restaurantService;
        this.productRepository = productRepository;
        this.productMapper = productMapper;
    }

    @PostMapping("{id}/products")
    public ResponseEntity<ProductDto> addProduct(@PathVariable Long id,
                                                 @Valid @RequestBody ProductDto productDto){
        Product product = this.restaurantService.addProduct(id, productMapper.productDtoToProduct(productDto));
        return new ResponseEntity<>(productMapper.productToProductDto(product), HttpStatus.CREATED);
    }

我有一个带有@ControllerAdvice 注释的自定义异常处理程序：

@ControllerAdvice
public class ExceptionControllerAdvice {
    @ExceptionHandler({MethodArgumentNotValidException.class})
    public ResponseEntity<Object> validationException(MethodArgumentNotValidException ex, WebRequest request) {
        ....
// here i format my custom error message
        return new ResponseEntity<>(apiError, new HttpHeaders(), apiError.getStatus());
    }

效果很好，如果验证失败，会向我发送此自定义响应：

{
    "status": "BAD_REQUEST",
    "errors": {
        "price": "doit être supérieur ou égal à 0",
        "name": "ne doit pas être nul",
        "category": "ne doit pas être nul"
    }
}

我正在尝试使用 mockMvc 来测试此测试的行为 class :

@ExtendWith(MockitoExtension.class)
class RestaurantsApiControllerTest {

    @Mock
    private RestaurantService restaurantService;
    @Mock
    private ProductRepository productRepository;
    @Mock
    private ProductMapper productMapper;
    @InjectMocks
    private RestaurantsApiController controller;

    MockMvc mockMvc;

    @BeforeEach
    void setUp() {
        mockMvc = MockMvcBuilders.standaloneSetup(controller).build();
    }

    @Test
    void givenInvalidFrom_whenAddProduct_ThenShouldThrowException() throws Exception {
        // productDto miss name, category and have negative value for price which is forbidden by validations annotations
        ProductDto productDto = ProductDto.builder().id(1L).price(-10.5D).build();

        MvcResult mvcResult = mockMvc.perform(post("/restaurants/1/products")
                .contentType(MediaType.APPLICATION_JSON)
                .content(asJsonString(productDto)))
                .andExpect(status().isBadRequest())
                .andReturn();

        String result = mvcResult.getResponse().getContentAsString();

        then(restaurantService).shouldHaveNoInteractions();
    }

测试完美通过，我可以在日志中看到正确预期的验证异常：

14:53:30.345 [main] WARN org.springframework.web.servlet.mvc.support.DefaultHandlerExceptionResolver - Resolved [org.springframework.web.bind.MethodArgumentNotValidException: Validation failed for argument ...
//I removed the rest of the message for readability, but each validation exception appears here properly
14:53:30.348 [main] DEBUG org.springframework.test.web.servlet.TestDispatcherServlet - Completed 400 BAD_REQUEST

但我找不到一种方法来测试我的错误图是否包含我期望的字段。当我尝试使用 :

检索响应正文时

String result = mvcResult.getResponse().getContentAsString();

字符串为空，我找不到任何测试响应正文的方法。

我完全不知道，如果能提供帮助，我们将不胜感激！

非常感谢！

Answer 1

MvcResult mvcResult = mockMvc.perform(post("/restaurants/1/products")
                .contentType(MediaType.APPLICATION_JSON)
                .content(asJsonString(productDto)))
                .andExpect(status().isBadRequest())
                .andExpect(content().string("Your content"))
                .andReturn();

或使用自定义匹配器

MvcResult mvcResult = mockMvc.perform(post("/restaurants/1/products")
                .contentType(MediaType.APPLICATION_JSON)
                .content(asJsonString(productDto)))
                .andExpect(status().isBadRequest())
                .andExpect(content().string(new CustomMatcher()))
                .andReturn();

    private static class ContentMatcher extends CustomMatcher<String>{

            public ContentMatcher() {
                super("");
            }

            @Override
            public boolean matches(Object o) {
                final String expected="Some long wide string " +
                        "wich i should check" +
                        "...."
                return o.equals(expected);
            }
        }

Answer 2

当您使用构建器配置 MockMvc 实例时，请进行以下更新：

MockMvcBuilders
    .standaloneSetup(controller)
    .setControllerAdvice(new ExceptionControllerAdvice())
    .build()

您应该手动将控制器建议设置为模拟 mvc 上下文，否则将被忽略。此次更新后，您将在错误响应中收到正文。如果你想验证 Json 正文，请使用 json 路径 API 就像上面的答案一样。

为什么 MockMvc 请求在测试成功时检索空的 responseBody？

Why MockMvc request retrieve empty responseBody while test succeed?

java

rest

spring-boot

mockmvc

junit5