Mockito简单使用

1. 简介

  1. Mockito框架
  • Mockito是一个强大的用于 Java 开发的 Mock 测试框架, 通过 Mockito 我们可以创建和配置 Mock 对象, 进而简化有外部依赖的类的测试
  • Mockito让我们得以避开数据库等的配置，保证我们的单测不依赖于外部条件。

  1. 常用注解

    • @Mock 创建 mock 对象
    • @InjectMocks 创建 mock 对象，属性含有被 @Mock 或 @Spy 标注的对象时会自动注入
    • @Spy 或 spy() 方法：封装 Java 对象，封装后对象的方法进行打桩，实际调用时会执行打桩方法
          @Test
    public void SpyTest(){
        
        List<Integer> list = new ArrayList<>();
        List<Integer> spy = spy(list);
        // 打桩
        doReturn("spy test").when(spy).get(anyInt());

        System.out.println(spy.get(1));
    }
    ```   
## 2. 使用

### 2.1 创建 mock 对象：Mockito 提供了两种方式创建 mock 对象
1. 使用静态方法 
   * `Mockito.mock(clazz)` 直接创建对象

    ```java
    jedis = mock(Jedis.class);
    jedisConnectionFactory = mock(JedisConnectionFactory.class);
    redisLock = new RedisLock(jedisConnectionFactory);

  2. 使用上面提到的两个注解

    • 使用@Mock, @InjectMocks 标注需要创建的对象
    • 调用 MockitoAnnotations.openMocks(this) 方法创建 mock 对象
    @Mock
private JedisConnectionFactory jedisConnectionFactory;

@Mock
private Jedis jedis;

@InjectMocks
private RedisLock redisLock;

@BeforeEach
public void setBefore() {

    MockitoAnnotations.openMocks(this);

    RedisConnection redisConnection = new JedisConnection(jedis) ;
    Mockito.when(jedisConnectionFactory.getConnection()).thenReturn(redisConnection);

    jedis = (Jedis)redisConnection.getNativeConnection();
}

2.2 Junit + Mockito

  1. 在测试类上使用注解：

    • Junit4: @RunWith(MockitoJUnitRunner.class)
    • Junit5: @ExtendWith(MockitoExtension.class)

    该注解作用同 MockitoAnnotations.openMocks(this) 方法, Mockito 文档：

    Until now in JUnit there were two ways to initialize fields annotated by Mockito annotations such as @Mock, @Spy, @InjectMocks, etc.

    • Annotating the JUnit test class with a @RunWith(MockitoJUnitRunner.class)
    • Invoking MockitoAnnotations.openMocks(Object) in the @Before method

  2. 创建 mock 对象

    • @Mock

    • @InjectMocks

      2.3 Spring Boot + Mockito

  3. @MockBean 将被标注对象放入 spring 容器中

  4. @SpyBean 封装对象

3. 应用

3.1 案例项目

  1. 说明：

    • 基于 Redis 的分布式锁
    • 代码是从 crossoverJie 大佬的GitHub项目 distributed-redis-tool 中抽取的

  2. 配置类

    @Configuration
public class RedisConfig {
 
    @Bean
    JedisConnectionFactory jedisConnectionFactory() {
        return new JedisConnectionFactory();
    }
}

  3. RedisLock 类

    @Component
public class RedisLock {

    private static Logger log = LoggerFactory.getLogger(RedisLock.class);

    private static final String SET_IF_NOT_EXIST = "NX";

    private static final String SET_WITH_EXPIRE_TIME = "EX";

    public static final String LOCK_MSG = "OK";

    private static final Long UNLOCK_MSG = 1L;

    private static final String LOCK_PREFIX = "lock_";

    // 过期时间(s)
    private static final int TIME = 10;

    // lua 脚本
    private static final String script = "if redis.call('get', KEYS[1]) == ARGV[1] then return redis.call('del', KEYS[1]) else return 0 end";

    private final JedisConnectionFactory jedisConnectionFactory;

    public RedisLock(JedisConnectionFactory jedisConnectionFactory) {
        this.jedisConnectionFactory = jedisConnectionFactory;
    }

    private Object getConnection(){

        RedisConnection redisConnection = jedisConnectionFactory.getConnection();
        Object connection = redisConnection.getNativeConnection();

        return connection;
    }

    /**
     * 分布式锁，加锁
     * @param key 锁唯一标识
     * @param request 线程唯一标识
     * @return
     */
    public boolean tryLock(String key, String request) {

        SetParams params = new SetParams().ex(TIME).nx();

        Jedis connection = (Jedis) this.jedisConnectionFactory.getConnection().getNativeConnection();
        String result = connection.set(LOCK_PREFIX + key, request, params);

        return LOCK_MSG.equals(result);
    }

    /**
     * 分布式锁，解锁
     * @param key 锁唯一标识
     * @param request 线程唯一标识
     * @return
     */
    public boolean unlock(String key, String request){

        Jedis connection = (Jedis) getConnection();

        Object result = connection.eval(script, Collections.singletonList(LOCK_PREFIX + key), Collections.singletonList(request));
        connection.close();

        return UNLOCK_MSG.equals(result);

    }
}

    3.2 单元测试

  4. Mockito.mock(clazz)

    public class MockitoMockTest {

    private Jedis jedis;

    private RedisLock redisLock;

    private JedisConnectionFactory jedisConnectionFactory;

    @BeforeEach
    public void setBefore() {

        jedis = mock(Jedis.class);
        jedisConnectionFactory = mock(JedisConnectionFactory.class);
        redisLock = new RedisLock(jedisConnectionFactory);

        RedisConnection redisConnection = new JedisConnection(jedis) ;
        Mockito.when(this.jedisConnectionFactory.getConnection()).thenReturn(redisConnection);

        jedis = (Jedis)redisConnection.getNativeConnection();
    }

    @Test
    public void redisLockTest(){

        Mockito.when(jedis.eval(Mockito.anyString(), Mockito.anyList(), Mockito.anyList())).thenReturn(1L) ;

        boolean unlock = redisLock.unlock("test", "ec8ebca0-14ba0-4b23-99a8-b35fbba3629e");

        assertTrue(unlock);

        Mockito.verify(jedis).eval(Mockito.anyString(), Mockito.anyList(), Mockito.anyList());
    }

    @Test
    public void redisUnlockTest(){

        when(jedis.set(anyString(), anyString(), any(SetParams.class))).thenReturn("OK");

        boolean lock = redisLock.tryLock("key", UUID.randomUUID().toString());

        assertTrue(lock);

        verify(jedis).set(anyString(), anyString(), any(SetParams.class));
    }

}

  5. MockitoAnnotations.openMocks(this)

    public class MockitoOpenMocksTest {

    @Mock
    private JedisConnectionFactory jedisConnectionFactory;

    @Mock
    private Jedis jedis;

    @InjectMocks
    private RedisLock redisLock;

    @BeforeEach
    public void setBefore() {

        MockitoAnnotations.openMocks(this);

        RedisConnection redisConnection = new JedisConnection(jedis) ;
        Mockito.when(jedisConnectionFactory.getConnection()).thenReturn(redisConnection);

        jedis = (Jedis)redisConnection.getNativeConnection();
    }

    @Test
    public void redisLockTest(){

        Mockito.when(jedis.eval(Mockito.anyString(), Mockito.anyList(), Mockito.anyList())).thenReturn(1L) ;

        boolean unlock = redisLock.unlock("test", "ec8ebca0-14ba0-4b23-99a8-b35fbba3629e");

        assertTrue(unlock);

        Mockito.verify(jedis).eval(Mockito.anyString(), Mockito.anyList(), Mockito.anyList());
    }

    @Test
    public void redisUnlockTest(){

        when(jedis.set(anyString(), anyString(), any(SetParams.class))).thenReturn("OK");

        boolean lock = redisLock.tryLock("key", UUID.randomUUID().toString());

        assertTrue(lock);

        verify(jedis).set(anyString(), anyString(), any(SetParams.class));
    }
}

  6. Junit + Mockito

    @ExtendWith(MockitoExtension.class)
public class JunitMockitoTest {

    @Mock
    private JedisConnectionFactory jedisConnectionFactory;

    @Mock
    private Jedis jedis;

    @InjectMocks
    private RedisLock redisLock;

    @BeforeEach
    public void setBefore() {

        RedisConnection redisConnection = new JedisConnection(jedis) ;
        Mockito.when(jedisConnectionFactory.getConnection()).thenReturn(redisConnection);

        jedis = (Jedis)redisConnection.getNativeConnection();
    }

    @Test
    public void redisLockTest(){

        Mockito.when(jedis.eval(Mockito.anyString(), Mockito.anyList(), Mockito.anyList())).thenReturn(1L) ;

        boolean unlock = redisLock.unlock("test", "ec8ebca0-14ba0-4b23-99a8-b35fbba3629e");

        assertTrue(unlock);

        Mockito.verify(jedis).eval(Mockito.anyString(), Mockito.anyList(), Mockito.anyList());
    }

    @Test
    public void redisUnlockTest(){

        when(jedis.set(anyString(), anyString(), any(SetParams.class))).thenReturn("OK");

        boolean lock = redisLock.tryLock("key", UUID.randomUUID().toString());

        assertTrue(lock);

        verify(jedis).set(anyString(), anyString(), any(SetParams.class));
    }
}

  7. Spring Boot + Mockito

    @SpringBootTest
public class SpringMockitoTest {

    @Mock
    private Jedis jedis;

    @Autowired
    private RedisLock redisLock;

    @MockBean
    private JedisConnectionFactory jedisConnectionFactory ;
    
    @BeforeEach
    public void setBefore() {

        MockitoAnnotations.openMocks(this);

        RedisConnection redisConnection = new JedisConnection(jedis) ;
        Mockito.when(jedisConnectionFactory.getConnection()).thenReturn(redisConnection);

        jedis = (Jedis)redisConnection.getNativeConnection();
    }

    @Test
    public void unlock() {

        Mockito.when(jedis.eval(Mockito.anyString(), Mockito.anyList(), Mockito.anyList())).thenReturn(1L) ;

        boolean unlock = redisLock.unlock("test", "ec8ebca0-14ba0-4b23-99a8-b35fbba3629e");

        assertTrue(unlock);

        Mockito.verify(jedis).eval(Mockito.anyString(), Mockito.anyList(), Mockito.anyList());
    }

    @Test
    public void lock() {
        Mockito.when(jedis.set(Mockito.anyString(), Mockito.anyString(), Mockito.any(SetParams.class))).thenReturn("OK");

        boolean tryLock = redisLock.tryLock("key", UUID.randomUUID().toString());

        assertEquals(true, tryLock);

        Mockito.verify(jedis).set(Mockito.anyString(), Mockito.anyString(), Mockito.any(SetParams.class));

    }
}

    相关链接

  8. Mockito官网

  9. Spring Boot Mock

  10. 基于 Redis 的分布式锁