如何为Spring MVC端点创建包含所需请求参数的单元测试，该请求参数包含JSON字符串？

Question

I understand that it is not good practice to have a request parameter that contains a JSON string but I have inherited this code so I have to work with it at the moment.

I am trying to create a unit test to test this endpoint but I am having an issue with the item request parameter:

The controller snippet is:

    @RequestMapping(value = "/item/{idtype}:{id}/details",
            method = RequestMethod.GET, produces="application/json; charset=UTF-8")
    @ApiOperation(value = "",
            response = ItemDTO.class, responseContainer = "List")
    @ApiImplicitParams({@ApiImplicitParam(name = "Authorization", value = "Authorization token",
            required = false, dataType = "string", paramType = "header")})
    public Collection<ItemDTO> getItemDetailList(@PathVariable("idtype") String idType, @PathVariable("id") String id,
                                                                   @RequestParam(value = "item", required = true) ItemDTO item {

   ...

   }
   ...
    @InitBinder("item")
    public void initBinder(WebDataBinder binder) {
        binder.registerCustomEditor(ItemDTO.class, new StringArrayPropertyEditor(null));
    }

The binder is used to convert the JSON string passed in the item parameter, to the ItemDTO java object.

The unit test snippet is:

private MockMvc mvc;

@Before
public void setUp() throws Exception {
    MockitoAnnotations.initMocks(this);
    mvc = MockMvcBuilders.standaloneSetup(ItemDetailsController).build();
}
...
StringBuilder stringBuilder = new StringBuilder("/v2/item/").append("type").append(":").append("1234")
    .append("/details");
Map<String, String> value = new HashMap<>();
value.put("value", "{\"itemId\":\"test\"}");
URI uri = new URI(stringBuilder.toString());
UriComponents uriComponents = UriComponentsBuilder.fromUri(uri).query("item={value}").buildAndExpand(value);
mvc.perform(MockMvcRequestBuilders.get(uriComponents.toUri())
    .contentType(MediaType.APPLICATION_JSON_VALUE))
    .andExpect(MockMvcResultMatchers.status().isOk()

When I run the unit test I get the exception:

java.lang.IllegalStateException: Cannot convert value of type [java.lang.String] to required type [biz.dto.ItemDTO]: no matching editors or conversion strategy found

I have tried other permutations and combinations, such as using chaining the .param method to the .perform method of mvc to add the item parameter or just simply adding the item parameter to the Stringbuilder but I have not had any success. I have also tried searching the forum for similar questions but I have had no success there either.

Any help would be greatly appreciated.

Answer 1

you are messing up your tests.

if you want to test binder - test binder. (mock test) if you want to test controller - test it. (mock test, again) What you want is full integration test, to see that binder is used by annotation and then parses string (json) into proper class. for that I would recommend RestAssured or something