java - 如何处理 org.mockito.exceptions.misusing.MissingMethodInitationException？

Question

我有一个看起来像这样的类(class)

@Stateless
@TransactionAttribute(TransactionAttributeType.REQUIRED)
public class ClientRegistrationManager {
    private CrudService crudService;
    private UniqueIdGenerator uniqueIdGenerator;

    @SuppressWarnings("UnusedDeclaration")
    public ClientRegistrationManager() {
    }

    @Inject
    public ClientRegistrationManager(@Nonnull final CrudService crudService, @Nonnull final UniqueIdGenerator uniqueIdGenerator) {
        this.crudService = crudService;
        this.uniqueIdGenerator = uniqueIdGenerator;
    }

    public Member register(@Nonnull final String email, @Nonnull final String userExternalId, @Nonnull final String password) {
        final Member existingMember;
        try {
            existingMember = getMemberQueries().getMemberByEmail(email);
        } catch (final NoResultException e) {
            return createNewMemberAndGetClientDetail(email, userExternalId);
        }
        return existingMember;
    }

    ...

    @Nonnull
    protected MemberQueries getMemberQueries() {
        return new MemberQueries(crudService);
    }
}

我想通过模拟任何外部行为来测试它，所以我创建了 getMemberQueries()使用 doc 中描述的模式 - 1

我，然后编写我的测试如下

public class ClientRegistrationManagerTest {

    @Mock
    private MemberQueries memberQueries;

    @Mock
    private CrudService crudService;

    @Mock
    private UniqueIdGenerator uniqueIdGenerator;

    @Before
    public void setUp() {
        MockitoAnnotations.initMocks(this);
    }

    @Test
    public void testMockedMemberQueries() {
        final ClientRegistrationManager clientRegistrationManager = new ClientRegistrationManager(crudService, uniqueIdGenerator);
        Mockito.when(clientRegistrationManager.getMemberQueries()).thenReturn(memberQueries);
        clientRegistrationManager.getMemberQueries();
        assertTrue(true);
    }
}

当我运行这个时，我得到的错误为

org.mockito.exceptions.misusing.MissingMethodInvocationException: 
when() requires an argument which has to be 'a method call on a mock'.
For example:
    when(mock.getArticles()).thenReturn(articles);

Also, this error might show up because:
1. you stub either of: final/private/equals()/hashCode() methods.
   Those methods *cannot* be stubbed/verified.
2. inside when() you don't call method on mock but on some other object.
3. the parent of the mocked class is not public.
   It is a limitation of the mock engine.

现在这意味着什么，我需要模拟整个 ClientRegistrationManager ，但是我想要测试的类，我不能只是模拟整个类。

我试图了解我的选择，我真的不想依赖 persistence层，太重了

Answer 1

Seelenvirtuose注释中是正确的:根本问题是您只能在模拟和 spy 上调用 when ，并且它通常是模拟被测类的反模式。

一种技术是使用 spy，它可以让您拦截并验证对真实对象的调用(“部分模拟”):

final ClientRegistrationManager clientRegistrationManager =
    Mockito.spy(new ClientRegistrationManager(crudService, uniqueIdGenerator);
// doReturn is important because the call to contains a call to the mock
// before Mockito has intercepted it. In your case, this may just create a useless
// real MemberQueries, but in other cases it can throw an exception.
Mockito.doReturn(memberQueries).when(clientRegistrationManager).getMemberQueries();

如Predrag Magic wrote ，另一种方法是创建一个工厂并在测试期间替换它。如果您将工厂作为可选构造函数参数传递，这尤其好，因为这样生产系统就可以创建并传递它们自己的 MemberQueryFactory，并且您的类仍将按预期工作。

public class ClientRegistrationManager {
  static class MemberQueriesFactory {
    MemberQueries getMemberQueries() {
      return ObjectFactory.newMemberQueries(crudService);
    }
  }

  /** Package-private. Visible for unit testing. */
  MemberQueriesFactory memberQueriesFactory = new MembersQueryFactory();
}

@RunWith(MockitoJUnitRunner.class)
public class ClientRegistrationManagerTest {
  @Mock ClientRegistrationManager.MembersQueryFactory mockMembersQueryFactory;

  private ClientRegistrationManager getManagerForTest() {
    ClientRegistrationManager manager = new ClientRegistrationManager();
    manager.memberQueriesFactory = mockMembersQueryFactory;
    return manager;
  }
}

不过，我最喜欢的方法是跳过 Mockito 并直接覆盖测试中的被测类:

@RunWith(MockitoJUnitRunner.class)
public class ClientRegistrationManagerTest {
  @Mock MemberQueries memberQueries;

  private ClientRegistrationManager getManagerForTest() {
    ClientRegistrationManager manager = new ClientRegistrationManager() {
      @Override void getMemberQueries() {
        return memberQueries;
      }
    };
  }
}