Spring Boot Controller Test with Mock Service doesn't use the mock service

Question

I have a simple RestController with a Service and want to test just the controller by providing a mock implementation for the Service. However, I'm getting an empty response in resultActions = mockMvc.perform(get("/user")); object when I'm running the test. Here is my code: Controller

@RestController
public class UserController {

    @Autowired
    UserService userService;

    @GetMapping("/user")
    public ResponseEntity<List<String>> getUsers(){
        return ResponseEntity.ok().body(userService.getUsers());
    }

}

Contoller Test

@RunWith(SpringRunner.class)
@WebMvcTest(UserController.class)
public class UserControllerTest {

    @MockBean
    UserService userService;

    private final Logger log = LoggerFactory.getLogger(UserControllerTest.class);
    @Autowired
    MockMvc mockMvc;

    @Before
    public void init(){
        List<String> usrs = new ArrayList<>();
        usrs.add("JUNIT-USER");
        userService = Mockito.mock(UserService.class);
        when(userService.getUsers()).thenReturn(usrs);
    }

    @Test
    public void test1() throws Exception {
        ResultActions resultActions = mockMvc.perform(get("/user"));
        resultActions.andDo(mvcResult -> {
            log.info(mvcResult.getResponse().getContentType());
            log.info(mvcResult.getResponse().getContentAsString());
            log.info(String.valueOf(mvcResult.getResponse().getContentLength()));

        });
        resultActions
        .andExpect(status().isOk())
        .andExpect(MockMvcResultMatchers.content().json("[\"JUNIT-USER\"]"));
    }

}

The output of the log statements in the test is as follows:

2021-02-24 15:23:16.161  INFO 22197 --- [           main] com.vi.learn.UserControllerTest      : application/json
2021-02-24 15:23:16.161  INFO 22197 --- [           main] com.vi.learn.UserControllerTest      : []
2021-02-24 15:23:16.161  INFO 22197 --- [           main] com.vi.learn.UserControllerTest      : 0

The test hence fails with the below assertionError: java.lang.AssertionError: []: Expected 2 values but got 0

What am I doing wrong here?

score 0 · Answer 1 · answered Feb 25 '21 at 09:03

Two existing methods

Using the mock () method
Using the @MockBean annotation

@MockBean
UserService userService;
or
userService = Mockito.mock(UserService.class);

You have to choose one of them so simply use @MockBean :

 @Before
public void init(){
    List<String> usrs = new ArrayList<>();
    usrs.add("JUNIT-USER");
    when(userService.getUsers()).thenReturn(usrs);
}

Spring Boot Controller Test with Mock Service doesn't use the mock service

1 Answers1