未调用java Mockito验证方法

Question

我是Mockito的初学者，正在尝试测试下面的课程

@Service
public class MyService {

public static final Logger logger = LoggerFactory.getLogger(MyService.class);

ObjectMapper objectMapper = new ObjectMapper(); 

public void logData(String personData) throws IOException{

    Person person = objectMapper.readValue(personData, Person.class);

    // log info
    logger.info("log person:  {}, {}", person.getName(), person.getAge());

 }
}

下面是我的测试类，我正在尝试测试是否调用ObjectMapper的readValue方法

@RunWith(MockitoJUnitRunner.class)
public class MyServiceTest {

public static final Logger logger = LoggerFactory.getLogger(MyServiceTest.class);

ObjectMapper objectMapper = mock(ObjectMapper.class);

MyService myService = new MyService();

@Test
public void verifyCallToReadValue() throws IOException{

    String personData = "{\"Name\":\"debieA\",\"Age\":\"31\"}";

    myService.logData(personData);

    verify(objectMapper, times(1)).readValue(personData, Person.class);
   }
 }

我得到的错误是“需要但未调用需要但未调用： 对象映射器。读取值（……）；"

如何解决此问题

Answer 1

必须将ObjectMappermock作为依赖项注入MyService

永远不要像在MyService（ObjectMapper objectMapper = new ObjectMapper()）中那样，使用new在类本身内部创建类的依赖项

请注意我在代码中的注释和更改：

@Service
public class MyService {

public static final Logger logger = LoggerFactory.getLogger(MyService.class);

//ObjectMapper objectMapper = new ObjectMapper(); //never do that
//instead init the field in the constructor using an external dependency
private ObjectMapper objectMapper;
public MyService(ObjectMapper objectMapper) {
    this.objectMapper = objectMapper;
}

public void logData(String personData) throws IOException{

    Person person = objectMapper.readValue(personData, Person.class);

    // log info
    logger.info("log person:  {}, {}", person.getName(), person.getAge());

 }
}

然后在测试中

@RunWith(MockitoJUnitRunner.class)
public class MyServiceTest {

public static final Logger logger = LoggerFactory.getLogger(MyServiceTest.class);

ObjectMapper objectMapper = mock(ObjectMapper.class);

@Test
public void verifyCallToReadValue() throws IOException{
    MyService myService = new MyService(objectMapper);
    // here you have to mock the readValue method. Something like this:
    //when(objectMapper.readValue(...)).thenReturn(new Person());
    String personData = "{\"Name\":\"debieA\",\"Age\":\"31\"}";

    myService.logData(personData);

    verify(objectMapper, times(1)).readValue(personData, Person.class);
   }
 }

Answer 2

使用@Spy注释，Spy非常聪明，可以调用

@Spy
ObjectMapper objectMapper = new ObjectMapper();

MyService myService = new MyService();

@Test
public void verifyCallToReadValue() throws IOException{

    String personData = "{\"Name\":\"debieA\",\"Age\":\"31\"}";

    myService.logData(personData);

    verify(objectMapper, times(1)).readValue(personData, Person.class);
   }
 }