如何使用 SpringJUnit4ClassRunner 将映射器（mapstruct）注入 Junit 测试

Question

I have problems with configuring tests for SpringJUnit4ClassRunner.class). My problem is because my mapper from map struct returns null when reached.

@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest
class UserServiceTestSuite {
    @Spy
    private UserDto userDto;
    @Spy
    private UserMapper userMapper;
    @Mock
    private UserRepository userRepository;
    @InjectMocks
    private UserService userService;

    private User createUser() {
        return User.builder()
                .firstName("Steve")
                .lastName("Jobs")
                .login("SteveJobs")
                .password("password")
                .role(UserRole.ROLE_ADMIN)
                .build();

    }

    @Test
    public void testCreateUser() {
        //Given
        User user = createUser();
        Mockito.when(userRepository.save(user)).thenReturn(user);
        //When
        UserDto userDto = userService.createUser(userMapper.mapToUserDto(user));
        Long id = userDto.getId();
        //Then
        Assert.assertEquals("Steve", userDto.getFirstName());
        Assert.assertEquals("Jobs", userDto.getLastName());
        Assert.assertEquals("SteveJobs", userDto.getLogin());
        Assert.assertEquals("ROLE_ADMIN", userDto.getRole());
    }

Answer 1

In my opinion you have two options:

1. Inject the mapper via @SpringBootTest(classes = {UserMapperImpl.class}) and
   @Autowired private UserMapper userMapper;
2. Simply initialize the Mapper private UserMapper userMapper = new UserMapperImpl() (and remove @Spy )

When using the second approach you can even remove the @SpringBootTest because in the given snippet you do not need a Spring context (created by the annotation).
@RunWith(MockitoJUnitRunner.class) can be used to automatically inject objects annotated with @Mock into your UserService . Writing unit tests without creating a spring context helps to keep test suite execution time low.

Answer 2

public interface UserMapper {
    UserMapper INSTANCE = Mappers.getMapper(UserMapper.class);
    UserDTO userMapper.mapToUserDto(Object value);
}

Using this mapper interface you can instantiate from the mock and use the methods. For example:

@Mock
private UserMapper userMapper;

Init the mocks:

@Before
public void setUp() {
   MockitoAnnotations.initMocks(this);
}

and you use the call INSTANCE

UserDto userDto = userService.createUser(userMapper.INSTANCE.mapToUserDto(user));