你必须这么做

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

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现在你可以获取user，并将其作为参数传递。

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

  }

}

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使用这种方法，你只需要确保你的mockedUserRepository被注入到你的测试类中（例如，在构造函数中）。

您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);
}

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场景二：findOneByLogin返回null对象：

@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);
}

型
场景二：保存完成时：
@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());
}

型

关于如何创建JPA存储库save方法，为@GeneratedValue字段生成随机ID，我只说两句。

/**
 * 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;
    });
}

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因此，这里您将所需的存储库作为参数传递，并且方法为所有使用@GeneratedValue annotation注解的字段调用enrichGeneratedValueField。下面是此方法的实现：

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) {
    }
}

型
在这个例子中，我只使用了Integer类型的ID，但是可以自由地添加你想要的ID类型。

要验证保存是否成功，也可以尝试以下操作

verify(repository, never()).save(savedEntity)

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