如何在单元测试中模拟 JPA 存储库的保存方法

Question

比如我在UserService中有这个方法：

  @Override
  @Transactional
  public UserDto create(UserDto userDto) {

    User dbUser = userRepository.findOne(userDto.getId());

    if (dbUser != null) {
      throw new AuthException(AuthException.ErrorCode.DUPLICATE_USER_EXCEPTION);
    }

    User oneByLogin = userRepository.findOneByLogin(userDto.getLogin());
    if (oneByLogin != null) {
      throw new AuthExceptionAuthException.ErrorCode.DUPLICATE_LOGIN_EXCEPTION);
    }

    User newUser = new User();
    newUser.setGuid(UUID.randomUUID().toString());
    newUser.setInsertDate(new Date());
    newUser.setFirstName(userDto.getFirstName());
    newUser.setLastName(userDto.getLastName());
    newUser.setLogin(userDto.getLogin());
    newUser.setPassword(userDto.getPassword());
    newUser.setAuthToken(TokenGenerator.nextToken());
    newUser.setAuthTokenCreatedDate(new Date());

    User savedUser = userRepository.save(newUser);

    userDto.setAuthToken(savedUser.getAuthToken());
    log.info("User {0} created", savedUser.getLogin());
    return userDto;
  }

如何为此方法创建单元测试？我接着试了：

  @Test
  public void createUser() {

    UserDto userDtoRequest = new UserDto();
    userDtoRequest.setLogin("Alex");
    userDtoRequest.setPassword("123");

    UserDto found = userService.create(userDtoRequest);
    assertThat(found.getAuthToken()).isNotEmpty();
}

我有下一个逻辑：

1. 测试开始
2. User dbUser = userRepository.findOne(userDto.getId()); dbUser = NULL
3. if (dbUser != null) 和 if (oneByLogin != null) 跳过
4. 创建新用户并设置数据
5. User savedUser = userRepository.save(newUser);savedUser = NULL

在这一步，我遇到了问题，因为我无法模拟 userRepository.save(newUser)。

newUser create inside the method. and test fail.

savedUser.getAuthToken() - savedUser == NULL

我可以重写：

    userRepository.save(newUser);
    userDto.setAuthToken(newUser.getAuthToken());
    log.info("User {0} created", newUser.getLogin());
    return userDto;

但是如果我想使用返回的对象savedUser呢？

Answer 1

你需要这样做。

when(userRepository.save(Mockito.any(User.class)))
                .thenAnswer(i -> i.getArguments()[0]);

现在您可以获得作为参数传递的用户。

Answer 2

您可以执行以下操作：

@RunWith(MockitoJUnitRunner.class)
public class SimpleTest {

  @Mock
  private UserRepository mockedUserRepository;

  // .. your test setup

  @Test
  public void testYourMethod() {

     User userToReturnFromRepository = new User();
     userToReturnFromRepository.setAuthToken(YOUR_TOKEN);
     when(mockedUserRepository.save(any(User.class)).thenReturn(userToReturnFromRepository);

     UserDto found = userService.create(userDtoRequest);

     // ... your asserts

  }

}

使用这种方法，您只需确保您的 mockedUserRepository 被注入到您的测试类中（例如在构造函数中）。

Answer 3

你需要编写多个测试用例来测试不同的场景。

场景 1：当 findOne 返回非空对象时：

@Test(expected=AuthException.class)
public void testCreateUserWhenAvailable()    {
     //Create one sample userDto object with test data
     when(mockedUserRepository.findOne(userDto.getId())).thenReturn(new User());
     userService.create(userDto);
}

场景 2：当 findOneByLogin 返回一个空对象时：

@Test(expected=AuthException.class)
public void testCreateUserWhenLoginAvailable()    {
     //Create one sample userDto object with test data
     when(mockedUserRepository.findOne(userDto.getId())).thenReturn(null);
     when(mockedUserRepository.findOneByLogin(userDto.getId())).thenReturn(new User());

     userService.create(userDto);
}

场景 2：save 完成后：

@测试

public void testCreateUserWhenSaved()    {
     //Create one sample userDto object with test data
     when(mockedUserRepository.findOne(userDto.getId())).thenReturn(null);
     when(mockedUserRepository.findOneByLogin(userDto.getId())).thenReturn(null);

     //Create sample User object and set all the properties
     User newUser=new User();
     when(mockedUserRepository.save(Mockito.any(User.class)).thenReturn(newUser);
     User returnedUser=userService.create(userDto);
     //You have two ways to test, you can either verify that save method was invoked by 
     //verify method
     verify(mockedUserRepository, times(1)).save(Mockito.any(User.class));
     //or by assertion statements, match the authToken in the returned object to be equal 
     //to the one set by you in the mocked object
     Assert.assertEquals(returnedUser.getAuthToken(),newUser.getAuthToken());
}

Answer 4

关于如何创建 JPA 存储库 save 方法并为带有 @GeneratedValue 的字段生成随机 ID，我只需 2 美分。

/**
 * Mocks {@link JpaRepository#save(Object)} method to return the
 * saved entity as it was passed as parameter and add generated ID to it.
 * If ID could not be generated, it will be ignored.
 * If parameter already has and ID, it will be overridden.
 */
private <T, V> void mockSave(JpaRepository<T, V> repository) {
    when(repository.save(any())).thenAnswer(i -> {
        Object argument = i.getArgument(0);
        Arrays.stream(argument.getClass().getDeclaredFields())
                .filter(f -> f.getAnnotation(GeneratedValue.class) != null)
                .forEach(f -> enrichGeneratedValueField(argument, f));
        return argument;
    });
}

因此，在这里您将所需的存储库作为参数传递，并且方法会为所有使用 @GeneratedValue 注释的字段调用 enrichGeneratedValueField。下面是这个方法的实现：

private void enrichGeneratedValueField(Object argument, Field field) {
    try {
        if (field.getType().isAssignableFrom(Integer.class)) {
            FieldUtils.writeField(field, argument, Math.abs(random.nextInt()), true);
        } else {
            FieldUtils.writeField(field, argument, mock(field.getType()), true);
        }
    } catch (Exception ignored) {
    }
}

在此示例中，我只使用了 Integer 类型的 ID，但可以随意填写以添加所需的 ID 类型。