Mockito+PowerMock+Junit单元测试

一、单元测试用途

1、日常开发团队要求规范，需要对开发需求代码进行单元测试并要求行覆盖率达到要求，DevOps流水线也会开设相关门禁阀值阻断代码提交，一般新增代码行覆盖率80%左右。

二、Mock测试介绍

1、Mock是为了解决不同的单元之间由于耦合而难于开发、测试的问题。所以，Mock既能出现在单元测试中，也会出现在集成测试、系统测试过程中。Mock 最大的功能是帮你把单元测试的耦合分解开，如果你的代码对另一个类或者接口有依赖，它能够帮你模拟这些依赖，并帮你验证所调用的依赖的行为。

2、Mock 测试就是在测试活动中，对于某些不容易构造或者不容易获取的比较复杂的数据/场景，用一个虚拟的对象(Mock对象)来创建用于测试的测试方法。

3、Mock重要作用

Mock是为了解决不同的单元之间由于耦合而难于开发、测试的问题。所以，Mock既能出现在单元测试中，也会出现在集成测试、系统测试过程中。

Mock 最大的功能是帮你把单元测试的耦合分解开，如果你的代码对另一个类或者接口有依赖，它能够帮你模拟这些依赖，并帮你验证所调用的依赖的行为。

三、Mock测试所需依赖

1、主要引入mockito-core/powermock-core

        <dependency>
            <groupId>org.mockito</groupId>
            <artifactId>mockito-core</artifactId>
            <version>4.5.1</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.powermock</groupId>
            <artifactId>powermock-core</artifactId>
            <version>2.0.9</version>
        </dependency>
        <dependency>
            <groupId>org.powermock</groupId>
            <artifactId>powermock-module-junit4</artifactId>
            <version>2.0.9</version>
        </dependency>
        <dependency>
            <groupId>org.powermock</groupId>
            <artifactId>powermock-api-mockito2</artifactId>
            <version>2.0.9</version>
            <scope>test</scope>
        </dependency>

Mockito和PowerMock都是单元测试模拟框架，用于模拟被测试类的依赖项。Mockito基于动态代理的方式实现，而PowerMock在Mockito基础上增加了类加载器以及字节码篡改技术，使其可以实现对private/static/final方法的Mock

四、Mock的核心功能

1、Mock对象创建

Mockito.mock(List.class); // Mock对象创建

public class VerifyMockExample {
    @Test
    public void testVerifyMock() {
        List<String> mockList = Mockito.mock(List.class);
        // 调用Mock对象的方法
        mockList.add("testCode");
        mockList.size();
        // 验证mockList.add("test")是否被调用过一次
        Mockito.verify(mockList,Mockito.times(1)).add("testCode");
        // 验证size()方法是否被调用过
        Mockito.verify(mockList,Mockito.times(1)).size();
        Assert.assertFalse(mockList.size()==1);
    }
}

verify系列方法

Mockito.verify/Mockito.times()验证调用次数

·verify(mock).methodCall()：验证方法被调用

· verify(mock, times(n)).methodCall()：验证方法被调用n次

· verify(mock, never()).methodCall()：验证方法从未被调用

或者是通过注解来实现创建

    @Mock
    private UserInfoMapper mockUserInfoMapper;

    @InjectMocks
    private UserInfoServiceImpl userInfoServiceImplUnderTest;

    @Test
    public void testVerifyMock2(){
        List<String> mockList = Mockito.mock(List.class);
        mockList.add("Code1");
        mockList.add("Code2");
        // 验证是否调用两次
        Mockito.verify(mockList,Mockito.times(2));
    }

 // 验证这个方法从没有被调用过
 Mockito.verify(userMapper, Mockito.never()).getUserById(1);

 userMapper.getUserById(1);
 // 验证这个方法至少调用了1次
 Mockito.verify(userMapper, Mockito.atLeastOnce()).getUserById(1);

 userMapper.getUserById(1);
 // 验证当前方法调用了2次
 Mockito.verify(userMapper, Mockito.times(2)).getUserById(1);

Mockito.when()使用when和thenReturn方法配置Mock对象的行为

Mockito.when( 对象.方法名 ).thenReturn( 自定义结果) //当调用了某个 Mock 对象的方法时，就回传我们想要的自定义结果。

thenReturn系列方法

//当使用任何整数值调用 userService 的 getUserById 方法时，就回传一个名字为 I'm mock 3 的 User 对象。
Mockito.when(userService.getUserById(Mockito.anyInt)).thenReturn( newUser( 3, "I'm mock"));
//限制只有当参数的数字是 3 时，才会回传名字为 I'm mock 3 的 user 对象。
Mockito.when(userService.getUserById( 3)).thenReturn( newUser( 3, "I'm mock"));
//当调用 userService 的 insertUser 方法时，不管传进来的 user 是什么，都回传 100。
Mockito.when(userService.insertUser(Mockito.any(User.class))).thenReturn( 100);

thenThrow系列方法

//当调用 userService 的 getUserById 时的参数是 8 时，抛出一个 RuntimeException。
Mockito.when(userService.getUserById( 8)).thenThrow( new RuntimeException( "mock throw exception"));
//如果方法没有返回值的话（即方法定义为 public void myMethod {...}），要改用 doThrow 抛出 Exception。
Mockito.doThrow( new RuntimeException( "mock throw exception")).when(userService.print);

    @Test
    public void testVerifyMock3(){
        List<String> mockList = Mockito.mock(List.class);
        // 设置Mock对象的预期行为
        Mockito.when(mockList.get(0)).thenReturn("mockedValue");
        // 断言验证返回值
        Assert.assertEquals("mockedValue",mockList.get(0));
    }

实战案例：测试一个UserInfoServiceImpl层saveUser()方法.

原始方法：

    @Transactional
    @Override
    public void saveUser(UserInfo userInfo){
        userInfoMapper.saveUser(userInfo);
    }

单元测试：

    @Test
    public void testSaveUser() {
        // Setup
        final UserInfo userInfo = new UserInfo();
        userInfo.setId(0);
        userInfo.setUserName("userName");
        userInfo.setCreateTime(new GregorianCalendar(2020, Calendar.JANUARY, 1).getTime());
        userInfo.setUpdateTime(new GregorianCalendar(2020, Calendar.JANUARY, 1).getTime());
        // Run the test
        userInfoServiceImplUnderTest.saveUser(userInfo);
        // Verify the results
        Mockito.verify(mockUserInfoMapper).saveUser(new UserInfo());
    }

原始方法：

    @Override
    public List<UserInfo> queryListByUserName(String userName) {
        return userInfoMapper.queryListByUserName(userName);
    }

单元测试方法：

    @Test
    public void testQueryListByUserName() {
        // Setup
        final UserInfo userInfo = new UserInfo();
        userInfo.setId(0);
        userInfo.setUserName("userName");
        userInfo.setCreateTime(new GregorianCalendar(2020, Calendar.JANUARY, 1).getTime());
        userInfo.setUpdateTime(new GregorianCalendar(2020, Calendar.JANUARY, 1).getTime());
        final List<UserInfo> expectedResult = Arrays.asList(userInfo);

        // Configure UserInfoMapper.queryListByUserName(...).
        final UserInfo userInfo1 = new UserInfo();
        userInfo1.setId(0);
        userInfo1.setUserName("userName");
        userInfo1.setCreateTime(new GregorianCalendar(2020, Calendar.JANUARY, 1).getTime());
        userInfo1.setUpdateTime(new GregorianCalendar(2020, Calendar.JANUARY, 1).getTime());
        final List<UserInfo> userInfos = Arrays.asList(userInfo1);
        when(mockUserInfoMapper.queryListByUserName("userName")).thenReturn(userInfos);
        // Run the test
        final List<UserInfo> result = userInfoServiceImplUnderTest.queryListByUserName("userName");
        // Verify the results
        assertThat(result).isEqualTo(expectedResult);
    }

    @Test
    public void testQueryListByUserName_UserInfoMapperReturnsNoItems() {
        // Setup
        when(mockUserInfoMapper.queryListByUserName("userName")).thenReturn(Collections.emptyList());
        // Run the test
        final List<UserInfo> result = userInfoServiceImplUnderTest.queryListByUserName("userName");
        // Verify the results
        assertThat(result).isEqualTo(Collections.emptyList());
    }

原始方法：

    @Override
    public List<UserInfo> queryUserInfoList(String createTime, List<Integer> idList) {
        return userInfoMapper.queryListByIds(createTime,idList);
    }

单元测试方法：

    @Test
    public void testQueryUserInfoList() {
        // Setup
        final UserInfo userInfo = new UserInfo();
        userInfo.setId(0);
        userInfo.setUserName("userName");
        userInfo.setCreateTime(new GregorianCalendar(2020, Calendar.JANUARY, 1).getTime());
        userInfo.setUpdateTime(new GregorianCalendar(2020, Calendar.JANUARY, 1).getTime());
        final List<UserInfo> expectedResult = Arrays.asList(userInfo);

        // Configure UserInfoMapper.queryListByIds(...).
        final UserInfo userInfo1 = new UserInfo();
        userInfo1.setId(0);
        userInfo1.setUserName("userName");
        userInfo1.setCreateTime(new GregorianCalendar(2020, Calendar.JANUARY, 1).getTime());
        userInfo1.setUpdateTime(new GregorianCalendar(2020, Calendar.JANUARY, 1).getTime());
        final List<UserInfo> userInfos = Arrays.asList(userInfo1);
        when(mockUserInfoMapper.queryListByIds("createTime", Arrays.asList(0))).thenReturn(userInfos);

        // Run the test
        final List<UserInfo> result = userInfoServiceImplUnderTest.queryUserInfoList("createTime", Arrays.asList(0));

        // Verify the results
        assertThat(result).isEqualTo(expectedResult);
    }

    @Test
    public void testQueryUserInfoList_UserInfoMapperReturnsNoItems() {
        // Setup
        when(mockUserInfoMapper.queryListByIds("createTime", Arrays.asList(0))).thenReturn(Collections.emptyList());

        // Run the test
        final List<UserInfo> result = userInfoServiceImplUnderTest.queryUserInfoList("createTime", Arrays.asList(0));

        // Verify the results
        assertThat(result).isEqualTo(Collections.emptyList());
    }

原始方法：Controller层，MockMvc

mockMvc.perform(request)：执行一个HTTP请求，并返回ResultActions对象。
ResultActions.andExpect(expected)：验证请求的处理结果，如状态码、响应体等。
ResultActions.andDo(handler)：处理请求的响应，如将响应体写入文件等。
ResultActions.andReturn()：返回已执行请求的结果，以便直接访问结果。
MockMvc.perform(request).andExpect(expected).andDo(handler).andReturn()：链式调用，执行请求、验证结果并处理响应，返回结果。


@Slf4j
@RestController
public class UserInfoController {
    @Autowired
    private UserInfoService userInfoService;

    /**
     * 查询全部列表
     * @return
     */
    @RequestMapping("/boot/query/users")
    public List<UserInfo> getUserInfoList(){
        List<UserInfo> list = userInfoService.list();
        return list;
    }

    /**
     * 保存用户信息
     * @return
     */
    @RequestMapping("/boot/save/user")
    public String saveUser(){
        try {
            UserInfo user=new UserInfo();
            user.setUserName("MyBatis Log Free");
            userInfoService.save(user);
        } catch (Exception e) {
            log.error("save user error", e);
            throw new GlobalException("save user error");
        }
        return "success";
    }

    @RequestMapping("/boot/query/users/ids")
    public List<UserInfo> getUserInfoListIds(){
        List<Integer> list = Arrays.asList(1, 3, 5);
        String createTime="2022-09-05 15:11:21";
        List<UserInfo> userInfos = userInfoService.queryUserInfoList(createTime,list);
        return userInfos;
    }

    @RequestMapping("/boot/query/users/like")
    public List<UserInfo> getUserInfoListLike(){
        List<UserInfo> infoList = userInfoService.queryListByUserName("A");
        return infoList;
    }

    @RequestMapping("/boot/save/userinfo")
    public void saveUserInfo(){
        UserInfo userInfo = new UserInfo();
        userInfo.setId(5);
        userInfo.setUserName("Puck");
        Date startTime = new Date();
        Date endTime = new Date();
        userInfo.setCreateTime(startTime);
        userInfo.setUpdateTime(endTime);
        userInfoService.saveUser(userInfo);
    }
}

单元测试方法如下:

@RunWith(SpringRunner.class)
@WebMvcTest(UserInfoController.class)
public class UserInfoControllerTest {

    @Autowired
    private MockMvc mockMvc;

    @MockBean
    private UserInfoService mockUserInfoService;

    @Test
    public void testGetUserInfoList() throws Exception {
        // Setup
        // Configure UserInfoService.list(...).
        final UserInfo userInfo = new UserInfo();
        userInfo.setId(0);
        userInfo.setUserName("MyBatis Log Free");
        userInfo.setCreateTime(new GregorianCalendar(2020, Calendar.JANUARY, 1).getTime());
        userInfo.setUpdateTime(new GregorianCalendar(2020, Calendar.JANUARY, 1).getTime());
        final List<UserInfo> userInfos = Arrays.asList(userInfo);
        when(mockUserInfoService.list()).thenReturn(userInfos);

        // Run the test
        final MockHttpServletResponse response = mockMvc.perform(get("/boot/query/users")
                        .accept(MediaType.APPLICATION_JSON))
                .andReturn().getResponse();

        // Verify the results
        assertThat(response.getStatus()).isEqualTo(HttpStatus.OK.value());
//        assertThat(response.getContentAsString()).isEqualTo("expectedResponse");
    }

    @Test
    public void testGetUserInfoList_UserInfoServiceReturnsNoItems() throws Exception {
        // Setup
        when(mockUserInfoService.list()).thenReturn(Collections.emptyList());

        // Run the test
        final MockHttpServletResponse response = mockMvc.perform(get("/boot/query/users")
                        .accept(MediaType.APPLICATION_JSON))
                .andReturn().getResponse();

        // Verify the results
        assertThat(response.getStatus()).isEqualTo(HttpStatus.OK.value());
        assertThat(response.getContentAsString()).isEqualTo("[]");
    }

    @Test
    public void testSaveUser() throws Exception {
        // Setup
        when(mockUserInfoService.save(new UserInfo())).thenReturn(false);

        // Run the test
        final MockHttpServletResponse response = mockMvc.perform(get("/boot/save/user")
                        .accept(MediaType.APPLICATION_JSON))
                .andReturn().getResponse();

        // Verify the results
        assertThat(response.getStatus()).isEqualTo(HttpStatus.OK.value());
        assertThat(response.getContentAsString()).isEqualTo("expectedResponse");
        verify(mockUserInfoService).save(new UserInfo());
    }

    @Test
    public void testGetUserInfoListIds() throws Exception {
        // Setup
        // Configure UserInfoService.queryUserInfoList(...).
        final UserInfo userInfo = new UserInfo();
        userInfo.setId(0);
        userInfo.setUserName("MyBatis Log Free");
        userInfo.setCreateTime(new GregorianCalendar(2020, Calendar.JANUARY, 1).getTime());
        userInfo.setUpdateTime(new GregorianCalendar(2020, Calendar.JANUARY, 1).getTime());
        final List<UserInfo> userInfos = Arrays.asList(userInfo);
        when(mockUserInfoService.queryUserInfoList("2022-09-05 15:11:21", Arrays.asList(0))).thenReturn(userInfos);

        // Run the test
        final MockHttpServletResponse response = mockMvc.perform(get("/boot/query/users/ids")
                        .accept(MediaType.APPLICATION_JSON))
                .andReturn().getResponse();

        // Verify the results
        assertThat(response.getStatus()).isEqualTo(HttpStatus.OK.value());
        assertThat(response.getContentAsString()).isEqualTo("expectedResponse");
    }

    @Test
    public void testGetUserInfoListIds_UserInfoServiceReturnsNoItems() throws Exception {
        // Setup
        when(mockUserInfoService.queryUserInfoList("2022-09-05 15:11:21", Arrays.asList(0)))
                .thenReturn(Collections.emptyList());

        // Run the test
        final MockHttpServletResponse response = mockMvc.perform(get("/boot/query/users/ids")
                        .accept(MediaType.APPLICATION_JSON))
                .andReturn().getResponse();

        // Verify the results
        assertThat(response.getStatus()).isEqualTo(HttpStatus.OK.value());
        assertThat(response.getContentAsString()).isEqualTo("[]");
    }

    @Test
    public void testGetUserInfoListLike() throws Exception {
        // Setup
        // Configure UserInfoService.queryListByUserName(...).
        final UserInfo userInfo = new UserInfo();
        userInfo.setId(0);
        userInfo.setUserName("MyBatis Log Free");
        userInfo.setCreateTime(new GregorianCalendar(2020, Calendar.JANUARY, 1).getTime());
        userInfo.setUpdateTime(new GregorianCalendar(2020, Calendar.JANUARY, 1).getTime());
        final List<UserInfo> userInfos = Arrays.asList(userInfo);
        when(mockUserInfoService.queryListByUserName("A")).thenReturn(userInfos);

        // Run the test
        final MockHttpServletResponse response = mockMvc.perform(get("/boot/query/users/like")
                        .accept(MediaType.APPLICATION_JSON))
                .andReturn().getResponse();

        // Verify the results
        assertThat(response.getStatus()).isEqualTo(HttpStatus.OK.value());
        assertThat(response.getContentAsString()).isEqualTo("expectedResponse");
    }

    @Test
    public void testGetUserInfoListLike_UserInfoServiceReturnsNoItems() throws Exception {
        // Setup
        when(mockUserInfoService.queryListByUserName("A")).thenReturn(Collections.emptyList());

        // Run the test
        final MockHttpServletResponse response = mockMvc.perform(get("/boot/query/users/like")
                        .accept(MediaType.APPLICATION_JSON))
                .andReturn().getResponse();

        // Verify the results
        assertThat(response.getStatus()).isEqualTo(HttpStatus.OK.value());
        assertThat(response.getContentAsString()).isEqualTo("[]");
    }

    @Test
    public void testSaveUserInfo() throws Exception {
        // Setup
        // Run the test
        final MockHttpServletResponse response = mockMvc.perform(get("/boot/save/userinfo")
                        .accept(MediaType.APPLICATION_JSON))
                .andReturn().getResponse();

        // Verify the results
        assertThat(response.getStatus()).isEqualTo(HttpStatus.OK.value());
        assertThat(response.getContentAsString()).isEqualTo("expectedResponse");
        verify(mockUserInfoService).saveUser(new UserInfo());
    }
}

@Mock用于模拟不属于 Spring 上下文的对象，而@MockBean用于模拟属于 Spring Boot 应用程序中的 Spring 上下文的对象。@MockBean提供与 Spring Boot 测试框架的无缝集成，并允许在测试期间用模拟对象轻松替换实际 bean

Mockito提供了多种参数匹配器（Matchers）用于更灵活的验证和配置行为：

import static org.mockito.ArgumentMatchers.*;
when(mockRepository.findById(anyInt())).thenReturn(Optional.of(user));
verify(mockRepository).findById(eq(1));

常见的匹配器包括：

　　·any()：匹配任何参数

　　· anyInt()：匹配任何整数参数

　　· eq(value)：匹配特定值

　　· isNull()：匹配null值

　　· notNull()：匹配非null值

Mock异常

Mockito.when(userMapper.getUserById(Mockito.anyInt())).thenThrow(new RuntimeException("运行时错误"));

Assertions.assertThrowsExactly(RuntimeException.class, () -> userMapper.getUserById(1));

// 对于没有返回值的方法，不能使用thenThrow()来抛出异常，可以使用doThrow()来抛出异常。
Mockito.doThrow(new RuntimeException("运行时错误")).when(userMapper).getUserById(1);
Assertions.assertThrowsExactly(RuntimeException.class, () -> userMapper.getUserById(1));

@MockBean 是 Spring Boot 提供的注解，它用于在测试中创建一个 mock 对象，并将其注入到 Spring 上下文中，替换掉原来的真实 Bean。需要使用SpringJUnit4ClassRunner.class之类的注解

@Mock: 用于代替Mockito.mock创建mock对象,创建一个Mock实例，需要基于JUnit5环境。@InjectMocks: 创建一个实例，其余用@Mock（或@Spy）注解创建的mock将被注入到用该实例中。

你要测试哪个类（如TemplateUserServiceImpl ），那么就用 @InjectMocks注解；被测试的类中通过 @Autowired注解注入了几个，那么测试类里面就用@Mock注解创建几个实例！

原始代码：

@Service
public class TemplateUserServiceImpl implements TemplateUserService {

    @Autowired
    private NamedParameterJdbcTemplate jdbcTemplate;

    @Transactional
    @Override
    public void saveUser() {
        UserInfo userInfo = new UserInfo();
        userInfo.setId(7);
        userInfo.setUserName("Boot");
        Date startTime = new Date();
        Date endTime = new Date();
        userInfo.setCreateTime(startTime);
        userInfo.setUpdateTime(endTime);
        // JdbcTemplate的写入datetime,使用in方式
//        String sql="insert into user_info(user_name,create_time,update_time) values(:user_name,:create_time,:update_time)";
        String sql="insert into user_info(user_name,create_time,update_time) values(:userName,:createTime,:updateTime)";
        SqlParameterSource sqlParameterSource=new BeanPropertySqlParameterSource(userInfo);
//        HashMap paramMap = new HashMap<>();
//        paramMap.put("user_name",userInfo.getUserName());
//        paramMap.put("create_time",userInfo.getCreateTime());
//        paramMap.put("update_time",userInfo.getUpdateTime());
//        jdbcTemplate.update(sql,paramMap);
        jdbcTemplate.update(sql,sqlParameterSource);
    }
}

对应单元测试代码：

import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.InjectMocks;
import org.mockito.Mock;
import org.mockito.junit.MockitoJUnitRunner;
import org.springframework.dao.DataAccessException;
import org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate;
import org.springframework.jdbc.core.namedparam.SqlParameterSource;

import static org.assertj.core.api.Assertions.assertThatThrownBy;
import static org.mockito.ArgumentMatchers.any;
import static org.mockito.ArgumentMatchers.eq;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.when;

@RunWith(MockitoJUnitRunner.class)
public class TemplateUserServiceImplTest {

    @Mock
    private NamedParameterJdbcTemplate mockJdbcTemplate;

    @InjectMocks
    private TemplateUserServiceImpl templateUserServiceImplUnderTest;

    @Test
    public void testSaveUser() {
        // Setup
        // Run the test
        templateUserServiceImplUnderTest.saveUser();

        // Verify the results
        verify(mockJdbcTemplate).update(
                eq("insert into user_info(user_name,create_time,update_time) values(:userName,:createTime,:updateTime)"),
                any(SqlParameterSource.class));
    }

    @Test
    public void testSaveUser_NamedParameterJdbcTemplateThrowsDataAccessException() {
        // Setup
        when(mockJdbcTemplate.update(
                eq("insert into user_info(user_name,create_time,update_time) values(:userName,:createTime,:updateTime)"),
                any(SqlParameterSource.class))).thenThrow(DataAccessException.class);

        // Run the test
        assertThatThrownBy(() -> templateUserServiceImplUnderTest.saveUser()).isInstanceOf(DataAccessException.class);
    }
}