Spring Boot 使用 Mockito 进行单元测试

示例

@ExtendWith({MockitoExtension.class})
public class HelloServiceTests {

    @InjectMocks
    private HelloService helloService = new HelloServiceImpl();

    @Mock
    private UserMapper userMapper;

    // @Spy
    // private HiService hiService = new HiServiceImpl();

    @Mock
    private HiService hiService = new HiServiceImpl();

    // @Spy
    // private HiService hiService;

    @BeforeEach
    public void init() {
        System.out.println("init");
        User mockUser = new User();
        mockUser.setId(2);
        Mockito.when(userMapper.getUserById(1)).thenReturn(mockUser);
    }

    // @BeforeAll 必须是 static 方法
    @BeforeAll
    public static void beforeAll() {
        System.out.println("beforeAll");
    }

    // @AfterAll 必须是 static 方法
    @AfterAll
    public static void afterAll() {
        System.out.println("afterAll");
    }

    @Test
    @DisplayName("测试接口1")
    public void test1() {
        Response response = helloService.sayHello(1);

        Assertions.assertEquals(2, ((User) response.getData()).getId());

    }

    @Test
    @DisplayName("测试接口2")
    public void test2() {
        Response response = helloService.sayHello(1);

        Assertions.assertNotEquals(3, ((User) response.getData()).getId());

    }

}

public interface HelloService {

    Response sayHello(int id);

}

@Service
public class HelloServiceImpl implements HelloService {

    @Resource
    private UserMapper userMapper;

    @Resource
    private HiService hiService;

    @Override
    public Response sayHello(int id) {
        System.out.println("HelloServiceImpl sayHello");
        hiService.sayHi();
        User user = userMapper.getUserById(id);
        return Response.builder().data(user).build();
    }
}

@Mapper
public interface UserMapper {

    @Select("select * from t_user where id = #{id}")
    User getUserById(@Param("id") int id);

}

public interface HiService {

    int sayHi();
}

@Service
public class HiServiceImpl implements HiService {
    @Override
    public int sayHi() {
        System.out.println("HiServiceImpl sayHi");
        return 100;
    }
}

@InjectMocks

需要被单元测试的类，该类中包含了其他依赖注入的组件，使用@InjectMocks表示其他依赖注入的组件是使用@Mock模拟的代理组件，不会走真实的方法。

@Mock

模拟的组件，通常是标注于@InjectMocks中注入的组件。会被代理，单元测试时不走真实方法。

比如模拟@Repository数据库访问对象，这样可以在单元测试时不链接数据库。

@Spy

真实对象，会走真实的方法。

注意：如果标注的是接口类型的组件，需要显示的new出实现类对象，否则@Spy的作用和@Mock一致。

MockitoExtension

@ExtendWith({MockitoExtension.class})表示使用Mockito功能