Mockito when().thenReturn() 在应该 return 空列表时返回 Null

Question

我一直在试图弄清楚为什么我的模拟 findIngredientsByCategory 方法 returning null 当我有 when(controller.findIngredientsByCategory(any()).thenReturn(Collections.emptyList()) 时。此实现适用于 findAll 方法。

下面是我的单元测试实现：

@RunWith(SpringJUnit4ClassRunner.class)
@WebMvcTest(IngredientController.class)
@ContextConfiguration(classes = {TestContext.class, WebApplicationContext.class})
@WebAppConfiguration
public class IngredientControllerTest {

  @Autowired
  private WebApplicationContext context;

  @Autowired
  private MockMvc mvc;

  @MockBean
  private IngredientController ingredientController;

  @Before
  public void setup() {
    MockitoAnnotations.initMocks(this);
    mvc = MockMvcBuilders.webAppContextSetup(context).build();
  }

  @Autowired
  private ObjectMapper mapper;

  private static class Behavior {
    IngredientController ingredientController;

    public static Behavior set(IngredientController ingredientController) {
      Behavior behavior = new Behavior();
      behavior.ingredientController = ingredientController;
      return behavior;
    }

    public Behavior hasNoIngredients() {
      when(ingredientController.getAllIngredients()).thenReturn(Collections.emptyList());
      when(ingredientController.getIngredientsByCategory(any())).thenReturn(Collections.emptyList());
      when(ingredientController.getIngredientById(anyString())).thenReturn(Optional.empty());
      return this;
    }
  }

  @Test
  public void getIngredientsByCategoryNoIngredients() throws Exception {
    Behavior.set(ingredientController).hasNoIngredients();
    MvcResult result = mvc.perform(get("/ingredients/filter=meat"))
        .andExpect(status().isOk())
        .andExpect(content().contentType(MediaType.APPLICATION_JSON_UTF8))
        .andReturn();
    String content = result.getResponse().getContentAsString();
    System.out.println(content);
 }

下面是控制器的实现：

@RestController
@RequestMapping("/ingredients")
public class IngredientController {

  @Autowired
  private IngredientRepository repository;

  @RequestMapping(value = "/filter", method = RequestMethod.GET)
  public List getIngredientsByCategory(@RequestParam("category") String category) {
    return repository.findByCategory(category);
  }
}

当我告诉它 return 一个空列表时，我不确定为什么模拟控制器在这个请求中 return 为 null。如果有人可以帮忙解决这个问题，我将不胜感激！谢谢

Answer 1

MockMvc 实际上会调用由 Spring 测试框架引导和创建的 IngredientController 但不会调用您用 [= 注释的模拟 IngredientController 14=]，所以你所做的所有存根都不会被调用。

其实@WebMvcTest的目的是为了测试@RestController及其相关的Spring配置是否正确，所以需要一个IngredientController的真实实例来创建而不是使用模拟的。相反，您应该模拟 IngredientController（即 IngredientRepository）内的依赖项。

因此，代码应如下所示：

@RunWith(SpringJUnit4ClassRunner.class)
@WebMvcTest(IngredientController.class)
@ContextConfiguration(classes = {TestContext.class, WebApplicationContext.class})
@WebAppConfiguration
public class IngredientControllerTest {

  @Autowired
  private WebApplicationContext context;

  @Autowired
  private MockMvc mvc;

  @MockBean
  private IngredientRepository ingredientRepository;


  @Test
  public void fooTest(){
    when(ingredientRepository.findByCategory(any()).thenReturn(Collections.emptyList())

    //And use the MockMvc to send a request to the controller, 
    //and then assert the returned MvcResult
  }

}

Answer 2

测试中的请求路径是“/ingredients/filter=meat”，但应该是“/ingredients/filter?category=meat”。所以，似乎 getIngredientsByCategory 没有被调用。

Mockito when().thenReturn() 在应该 return 空列表时返回 Null

Mockito when().thenReturn() Returning Null when it should return empty list

java

spring

unit-testing

mockito

spring-mvc-test