III.使用Mock，在执行单元测试前，将依赖但又没办法获取到实现类的 bean 注入进去。
将mokito包加入项目。
<!-- https://mvnrepository.com/artifact/org.mockito/mockito-inline -->
<dependency>
<groupId>org.mockito</groupId>
<artifactId>mockito-inline</artifactId>
<version>4.5.1</version>
<scope>test</scope>
</dependency>
<!-- https://mvnrepository.com/artifact/org.mockito/mockito-core -->
<dependency>
<groupId>org.mockito</groupId>
<artifactId>mockito-core</artifactId>
<version>4.5.1</version>
<scope>test</scope>
</dependency>
<!-- https://mvnrepository.com/artifact/net.bytebuddy/byte-buddy-agent -->
<dependency>
<groupId>net.bytebuddy</groupId>
<artifactId>byte-buddy-agent</artifactId>
<version>1.12.9</version>
<scope>test</scope>
</dependency>
<!-- https://mvnrepository.com/artifact/net.bytebuddy/byte-buddy -->
<dependency>
<groupId>net.bytebuddy</groupId>
<artifactId>byte-buddy</artifactId>
<version>1.12.8</version>
</dependency>
使用 @MockBean 和 MockitoAnnotations.openMocks(this) 可以将依赖的 bean 注入进去。
@ExtendWith(SpringExtension.class)
@SpringBootTest(classes = CommonTestApplication.class)
public class CommonEntityServiceTest {
private final Logger logger = LoggerFactory.getLogger(this.getClass());
@Autowired
private CommonEntityService commonEntityService;
@MockBean
public WebRpc webRpc;
@MockBean
public WebRpc2 webRpc2;
@BeforeEach
public void before(){
MockitoAnnotations.openMocks(this);
}
@Test
public void test() {
ApiResult<Void> testSuccess = commonEntityService.test(new CommonEntity());
Assert.isTrue(testSuccess.getSuccess(), "testSuccess fail");
logger.info("testSuccess: {}", JSON.toJSONString(testSuccess));
}
}
此时再执行 test() 方法，不再出现 NoSuchBeanDefinitionException 异常，但会出现 NullPointerException 异常。这是因为我们虽然注入了 bean，但这个 bean 是个空的，因此在 commonEntityService.test 方法中执行 webRpc.get() 时，会报 NullPointerException 异常。为解决这个问题，我们可以继续使用 mock，Mockito.when(). thenReturn()。
@ExtendWith(SpringExtension.class)
@SpringBootTest(classes = CommonTestApplication.class)
public class CommonEntityServiceTest {
private final Logger logger = LoggerFactory.getLogger(this.getClass());
@Autowired
private CommonEntityService commonEntityService;
@MockBean
public WebRpc webRpc;
@MockBean
public WebRpc2 webRpc2;
@BeforeEach
public void before(){
MockitoAnnotations.openMocks(this);
}
@Test
public void test() {
Mockito.when(webRpc.get()).thenReturn(ApiResult.success("mock result 1"));
Mockito.when(webRpc.get2("test")).thenReturn(ApiResult.success("mock result 2"));
ApiResult<Void> testSuccess = commonEntityService.test(new CommonEntity());
Assert.isTrue(testSuccess.getSuccess(), "testSuccess fail");
logger.info("testSuccess: {}", JSON.toJSONString(testSuccess));
}
}
再次执行 test() 方法，此时执行已经成功了，打印日志如下所示。
2022-05-21 22:23:23.094 INFO 3760 --- [ main] c.p.j.s.c.c.s.i.CommonEntityServiceImpl : insert 0 common entity
2022-05-21 22:23:23.161 INFO 3760 --- [ main] c.p.j.s.c.c.s.CommonEntityServiceTest : apiResult: {"code":"200","msg":"调用成功","success":true}
虽然已经成功执行了单元测试，但如果需要 mock 的 bean 很多的话，那不是每个测试类都需要写一遍 mock，很浪费时间啊，因此，我们可以把需要 mock 的 bean 全都放到一个类中进行管理。
@Component
public class CommonMockFactory {
@BeforeEach
public void before(){
MockitoAnnotations.openMocks(this);
}
@MockBean
public WebRpc webRpc;
@MockBean
public WebRpc2 webRpc2;
}
然后在需要单元测试的类中进行注入即可。
@ExtendWith(SpringExtension.class)
@SpringBootTest(classes = CommonTestApplication.class)
public class CommonEntityServiceTest {
private final Logger logger = LoggerFactory.getLogger(this.getClass());
@Autowired
private CommonEntityService commonEntityService;
@Autowired
private CommonMockFactory commonMockFactory;
@Test
public void test() {
Mockito.when(commonMockFactory.webRpc.get()).thenReturn(ApiResult.success("mock result 1"));
Mockito.when(commonMockFactory.webRpc.get2("test")).thenReturn(ApiResult.success("mock result 2"));
ApiResult<Void> testSuccess = commonEntityService.test(new CommonEntity());
Assert.isTrue(testSuccess.getSuccess(), "testSuccess fail");
logger.info("testSuccess: {}", JSON.toJSONString(testSuccess));
}
}
2-3.提高单元测试覆盖率
使用idea自带的单元测试覆盖率工具可以查看相应的覆盖率。绿色的条代表已覆盖，红色的条代表未覆盖。
以下是单元测试的覆盖率文档，分别是类覆盖率、方法覆盖率、行覆盖率，从图中可以看出我们的行覆盖率只有64%，还有提升的空间。
如何提升呢？答案就是 mock。
先上改造后的代码：
@ExtendWith(SpringExtension.class)
@SpringBootTest(classes = CommonTestApplication.class)
public class CommonEntityServiceTest {
private final Logger logger = LoggerFactory.getLogger(this.getClass());
@Autowired
private CommonEntityService commonEntityService;
@Autowired
private CommonMockFactory commonMockFactory;
@Test
public void test() {
Mockito.when(commonMockFactory.webRpc.get()).thenReturn(ApiResult.success("mock result 1"));
Mockito.when(commonMockFactory.webRpc.get2("test")).thenReturn(ApiResult.success("mock result 2"));
ApiResult<Void> testSuccess = commonEntityService.test(new CommonEntity());
Assert.isTrue(testSuccess.getSuccess(), "testSuccess fail");
logger.info("testSuccess: {}", JSON.toJSONString(testSuccess));
}
@Test
public void testWithMock() {
Mockito.when(commonMockFactory.webRpc.get()).thenReturn(ApiResult.success("mock result 1"));
Mockito.when(commonMockFactory.webRpc.get2("test")).thenReturn(ApiResult.success("mock result 2"));
ApiResult<Void> testSuccess = commonEntityService.test(new CommonEntity());
Assert.isTrue(testSuccess.getSuccess(), "testSuccess fail");
logger.info("testSuccess: {}", JSON.toJSONString(testSuccess));
// 模拟 webRpc.get() 失败
Mockito.when(commonMockFactory.webRpc.get()).thenReturn(ApiResult.error(BizRespStatusEnum.ILLEGAL_PARAM));
Mockito.when(commonMockFactory.webRpc.get2("test")).thenReturn(ApiResult.success("mock result 2"));
ApiResult<Void> testFail1 = commonEntityService.test(new CommonEntity());
Assert.isTrue(!testFail1.getSuccess(), "testFail1 fail");
logger.info("testFail1: {}", JSON.toJSONString(testFail1));
Mockito.when(commonMockFactory.webRpc.get()).thenReturn(ApiResult.success("mock result 1"));
// 模拟 webRpc.get2() 失败
Mockito.when(commonMockFactory.webRpc.get2("test")).thenReturn(ApiResult.error(BizRespStatusEnum.ILLEGAL_PARAM));
ApiResult<Void> testFail2 = commonEntityService.test(new CommonEntity());
Assert.isTrue(!testFail2.getSuccess(), "testFail1 fail");
logger.info("testFail2: {}", JSON.toJSONString(testFail2));
Mockito.when(commonMockFactory.webRpc.get()).thenReturn(ApiResult.success("mock result 1"));
Mockito.when(commonMockFactory.webRpc.get2("test")).thenReturn(ApiResult.success("mock result 2"));
try (MockedStatic<RmiUtil> rmiUtilMockedStatic = Mockito.mockStatic(RmiUtil.class)) {
// 模拟 RmiUtil.getRemoteResult() 失败
rmiUtilMockedStatic.when(RmiUtil::getRemoteResult).thenReturn(Optional.empty());
ApiResult<Void> testFail3 = commonEntityService.test(new CommonEntity());
Assert.isTrue(!testFail3.getSuccess(), "testFail3 fail");
logger.info("testFail3: {}", JSON.toJSONString(testFail3));
}
}
}
单元测试的执行结果。
2022-05-21 23:23:46.516 INFO 35136 --- [ main] c.p.j.s.c.c.s.i.CommonEntityServiceImpl : insert 0 common entity
2022-05-21 23:23:46.589 INFO 35136 --- [ main] c.p.j.s.c.c.s.CommonEntityServiceTest : testSuccess: {"code":"200","msg":"调用成功","success":true}
2022-05-21 23:23:46.590 INFO 35136 --- [ main] c.p.j.s.c.c.s.i.CommonEntityServiceImpl : getRpc fail: ApiResult{success=false, code='400', msg='参数异常', result=null}
2022-05-21 23:23:46.590 INFO 35136 --- [ main] c.p.j.s.c.c.s.CommonEntityServiceTest : testFail1: {"code":"400","msg":"参数异常","success":false}
2022-05-21 23:23:46.591 INFO 35136 --- [ main] c.p.j.s.c.c.s.i.CommonEntityServiceImpl : getRpc2 fail: ApiResult{success=false, code='400', msg='参数异常', result=null}
2022-05-21 23:23:46.591 INFO 35136 --- [ main] c.p.j.s.c.c.s.CommonEntityServiceTest : testFail2: {"code":"400","msg":"参数异常","success":false}
2022-05-21 23:23:46.629 INFO 35136 --- [ main] c.p.j.s.c.c.s.i.CommonEntityServiceImpl : getRemoteResult fail
2022-05-21 23:23:46.629 INFO 35136 --- [ main] c.p.j.s.c.c.s.CommonEntityServiceTest : testFail3: {"code":"002","msg":"系统异常","success":false}
再来看看改造之后的覆盖率！从下图中可以看出单元测试的行覆盖率达到了100%，惊不惊喜，意不意外！
3、总结
在我们没用 mock 工具时，别说覆盖率了，执行一个单元测试都很麻烦。
使用 mock 工具之后，我们不仅可以很方便的执行单元测试，还能使用各种奇技淫巧来提升行覆盖率，强烈推荐！
写好单元测试一点都不简单，本文只是拿了一个简单的场景来举例，在单元测试的行覆盖率达到100%时，代码量就已经是源码的两倍还多了，害！但是 bug 和单元测试总要选一个的,就看大家的选择了~
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