[开发测试]Powermockito和Mockito单元测试框架实战

1.Powermockito和Mockito之间的关系可以参考我的另一篇博客

Powermockito和Mockito测试框架分析以及一个简单的脚手架+单测的注意事项

2.maven依赖配置

<dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.13.1</version>
            <scope>test</scope>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.powermock/powermock-api-mockito2 -->
        <dependency>
            <groupId>org.powermock</groupId>
            <artifactId>powermock-api-mockito2</artifactId>
            <version>2.0.9</version>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.powermock</groupId>
            <artifactId>powermock-module-junit4</artifactId>
            <version>2.0.9</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.assertj</groupId>
            <artifactId>assertj-core</artifactId>
            <version>3.19.0</version>
            <scope>test</scope>
        </dependency>
    </dependencies>

3.java 代码准备

@Repository
public interface UserDAO {
    UserDTO getById(Long userId);
}

@Data
@AllArgsConstructor
@NoArgsConstructor
public class UserDTO {
    private Long userId;
    private String username;
}

@Service
public class UserService {
    @Resource
    private UserDAO userDAO;

    public UserDTO getById(Long userId) {
        if (Objects.isNull(userId) || userId == 0l) {
            return new UserDTO(1l, "zxliuyu");
        }
        return userDAO.getById(userId);
    }
     public UserDTO getByIdAllowException(Long userId) {
        if (Objects.isNull(userId) || userId == 0l) {
            throw new RuntimeException("用户Id不能为空");
        }

        return userDAO.getById(userId);
    }
    public UserDTO getByIdUseStaticMethod(Long userId) {
        userId = HttpClient.getUserId();
        return userDAO.getById(userId);
    }
    public UserDTO getByIdContainInternalCall(Long userId) {
        userId = getUserId();
        return userDAO.getById(userId);
    }

    public Long getUserId() {
        return 1l;
    }
}

4.单元测试代码

@RunWith(PowerMockRunner.class)
@PrepareForTest(HttpClient.class)
public class UserServiceTest {
    @InjectMocks
    private UserService userService;
    @Mock
    private UserDAO userDAO;
    @Rule
    public ExpectedException exception = ExpectedException.none();

    @Before
    public void init() {
        MockitoAnnotations.initMocks(this);
        PowerMockito.mockStatic(HttpClient.class);
    }

    @Test
    public void testGetByIdUserIdIsNull() {
        // Give
        Long userId = null;
        long expectedUserId = 1l;

        // When
        UserDTO user = userService.getById(userId);

        // Then
        Mockito.verify(userDAO, Mockito.times(0)).getById(any());
        Assertions.assertThat(user.getUserId()).isEqualTo(expectedUserId);
    }

    @Test
    public void testGetById() {
        // Give
        Long userId = 1l;
        long expectedUserId = 1l;

        // When
        when(userDAO.getById(any())).thenReturn(new UserDTO(1l, "zxliuyu"));
        UserDTO user = userService.getById(userId);

        // Then
        Mockito.verify(userDAO, Mockito.times(1)).getById(any());
        Assertions.assertThat(user.getUserId()).isEqualTo(expectedUserId);
    }

    @Test
    public void testGetByIdAllowExceptionUserIdIsNull() {
        // Give
        Long userId = null;

        // When
        exception.expect(RuntimeException.class);
        exception.expectMessage("用户Id不能为空");
        userService.getByIdAllowException(userId);

        // Then 如果是抛异常的可以没有then
    }

    @Test
    public void testGetByIdAllowException() {
        // Give
        Long userId = 1l;
        long expectedUserId = 1l;

        // When
        when(userDAO.getById(any())).thenReturn(new UserDTO(1l, "zxliuyu"));
        UserDTO user = userService.getByIdAllowException(userId);

        // Then
        Mockito.verify(userDAO, Mockito.times(1)).getById(any());
        Assertions.assertThat(user.getUserId()).isEqualTo(expectedUserId);
    }

    @Test
    public void testGetByIdUseStaticMethod() {
        // Give
        Long userId = 1l;
        long expectedUserId = 1l;

        // When
        when(userDAO.getById(any())).thenReturn(new UserDTO(1l, "zxliuyu"));
        when(HttpClient.getUserId()).thenReturn(userId);
        UserDTO user = userService.getByIdUseStaticMethod(userId);

        // Then
        Mockito.verify(userDAO, Mockito.times(1)).getById(any());
        Assertions.assertThat(user.getUserId()).isEqualTo(expectedUserId);
    }

    @Test
    public void testGetByIdContainInternalCall() {
        // Give
        Long userId = 1l;
        long expectedUserId = 1l;

        // When 如果出现方法内部调用，需要使用spy进行打桩，然后该类所有的方法都用打桩后的对象调用
        UserService userServiceSpy = PowerMockito.spy(userService);
        when(userDAO.getById(any())).thenReturn(new UserDTO(1l, "zxliuyu"));
        doReturn(userId).when(userServiceSpy).getUserId();
        UserDTO user = userServiceSpy.getByIdContainInternalCall(userId);

        // Then
        Mockito.verify(userDAO, Mockito.times(1)).getById(any());
        Assertions.assertThat(user.getUserId()).isEqualTo(expectedUserId);
    }
}

执行结果

5.注意事项

1.如果出现方法内部调用，需要使用spy进行打桩，然后该类所有的方法都用打桩后的对象调用

doReturn(userId).when(userServiceSpy).getUserId();

2.尽量不要mock使用私有方法，会有一些问题，如果私有方法需要单元测试，建议改成公共方法,加上VisibleForTesting代表这个方法是为了测试才改成公共方法

	@VisibleForTesting
    public Long getUserId() {
        return 1l;
    }