我如何测试一个采用Multipartfile等参数的post api方法。根据Spring文档，我知道我必须使用multipart而不是post for MockMvc，但是我的响应状态是400而不是200。（请随意使用您自己的示例来给予我如何测试这个）。
测试类和方法

@Autowired
private MockMvc mockMvc;

@MockBean
private ProductService productService;

@Test
void newProduct() {
        // Given
        Product product = new Product("Test", "Diary", "Lorem 24", "fresh-pepper.jpg");
        product.setId(1L);
        product.setPath("dummy photo path");
        MockMultipartFile multipartFile = new MockMultipartFile("file",
                "fresh-pepper.jpg",
                "image/png, image/jpg, image/jpeg",
                "random image".getBytes());
        //When
        when(productService.saveProduct(product, multipartFile)).thenReturn(product);

        //Then
        try {
            this.mockMvc.perform(multipart("/dummy/api/v1/addNew")
                    .file(multipartFile))
                    .andDo(print())
                    .andExpect(status().isOk());

        } catch (Exception e) {
            e.printStackTrace();
        }

}

Rest API方法和NOTE @RequestMapping("/dummy/api/v1")

@PostMapping(path = "/addNew", consumes = {MULTIPART_FORM_DATA_VALUE})
    public ResponseEntity<Product> newProduct(@Valid Product product,
                                              BindingResult bindingResult,
                                              @RequestParam("file") MultipartFile file) {
        if (bindingResult.hasFieldErrors()){
            bindingResult.getFieldErrors().forEach(fieldError -> LOGGER.error("Error " + fieldError.getField()));
            return new ResponseEntity<>(HttpStatus.BAD_REQUEST);
        }

        return new ResponseEntity<>(productService.saveProduct(product, file), HttpStatus.OK);
    }