单元测试错误：java.util.NoSuchElementException：java.util.Optional.get 中没有值

Question

我正在尝试在下面对我的对象服务进行单元测试：

@Service
public class ObjectServiceImpl implements ObjectService{

  private final ObjectDao objectDao;

  @Autowired
  public ObjectServiceImpl(ObjectDao objectDao){
    this.objectDao = objectDao;
  }

  @Override
    public Object getById(Long ObjectId) throws RecordNotFoundException {
        Optional<Object> Object = ObjectDao.findById(ObjectId);
        if (!Object.isPresent()) {
            throw new RecordNotFoundException(String.format(
                    MessageConstants.ObjectID_NOT_FOUND, ObjectId));
        }
        return Object.get(); 
    }

但是当我尝试在下面实现我的 JUnit 时出现错误：No value present at java.util.Optional.get：

@RunWith(MockitoJUnitRunner.Silent.class)
public class ObjectServiceTest {

    @InjectMocks
    private ObjectServiceImpl objectServiceImpl;

    @Mock
    private ObjectDao objectDao;

    private ObjectService objectService;

    @Test
    public void getById() throws RecordNotFoundException{
        Object object = new Object();
        Long objectId = 1L;
        Optional<Object> objectList =
            objectDao.findById(objectId);
        given(objectDao.findById(
                    objectList.get().getId())).willReturn(objectList);
        objectServiceImpl.getById(Mockito.anyLong());
        Mockito.verify(objectDao).findById(objectId);
        assertNotNull(objectServiceImpl.getById(objectId));
    }
}

我有什么遗漏或需要更新的吗？

Answer 1

您应该在这里做的第一件事是为objectList 创建一个存根。

之后您将描述objectDao 的行为，并执行验证。我的解决方案是：

       @Test
       public void getById() throws RecordNotFoundException{
         // if it's List in your case
         Optional<Object> objectList = Optional.of(Arrays.asList(new YourType()));              
         given(objectDao.findById(Mockito.anyLong())).willReturn(objectList); 
         Object returnedObject = objectServiceImpl.getById(1L);
         Mockito.verify(objectDao).findById(Mockito.anyLong());
         assertNotNull(returnedObject);
      }

注意 1：在您的测试开始时有多余（从未使用过）的对象

注2：注意Mockito.anyLong()的用法，我认为这更适合您的情况（用于测试service.getById();）

Answer 2

这两种说法都不正确。

 Optional<Object> objectList =
        objectDao.findById(objectId);
 given(objectDao.findById(
        objectList.get().getId())).willReturn(objectList); 

首先，您尝试在模拟（objectDao）上执行 findById，然后模拟调用此函数时需要返回的内容。

解决这个问题的一种方法是

 @Test
   public void getById() throws RecordNotFoundException{
     Object object = new Object();
     Long objectId = 1L;
     Optional<Object> objectList = // create a object of Type Object manually and assign it 
     given(objectDao.findById(
        objectId)).willReturn(objectList); 
     Object returnedobject = objectServiceImpl.getById(objectId);
     Mockito.verify(objectDao).findById(objectId);
     assertNotNull(returnedobject);
  }