使用 mockito 和事件监听器进行单元测试 MVP

Question

Android Studio 2.1.2

我想测试一下 LoginModelImp 中的回调 onUsernameError、onPasswordError 和 onSuccess 是否真的被调用了。我不确定如何测试事件侦听器。但是，测试失败，因为这些函数从未被调用过。我正在用 mockito 嘲笑他们并试图验证他们。

到目前为止，这是我的代码。

演示者界面

public interface LoginPresenterContract<LoginFragmentViewContract> {
    void validateCredentials();

    void attachView(LoginFragmentViewContract view);
    void detachView();
}

Presenter 实现

public class LoginPresenterImp implements LoginPresenterContract<LoginFragmentViewContract>, LoginModelContract.OnLoginCompletedListener {

    private LoginModelContract mLoginModelContract;
    private LoginFragmentViewContract mLoginFragmentView;

    public LoginPresenterImp(LoginModelContract loginModelContract) {
        mLoginModelContract = loginModelContract;
    }

    /*
     * LoginPresenterContact - implementation
     */
    @Override
    public void attachView(LoginFragmentViewContract view) {
        mLoginFragmentView = view;
    }

    @Override
    public void detachView() {
        mLoginFragmentView = null;
    }

    @Override
    public void validateCredentials() {
        if(mLoginModelContract != null) {
            mLoginModelContract.login(
                    mLoginFragmentView.getUsername(),
                    mLoginFragmentView.getPassword(),
                    LoginPresenterImp.this);
        }
    }

    /*
     * LoginModelContract.OnLoginCompletedListener - implementation
     */
    @Override
    public void onUsernameError() {
        if(mLoginFragmentView != null) {
            mLoginFragmentView.onLoginFailed("Incorrect username");
        }
    }

    @Override
    public void onPasswordError() {
        if(mLoginFragmentView != null) {
            mLoginFragmentView.onLoginFailed("Incorrect password");
        }
    }

    @Override
    public void onSuccess() {
        if(mLoginFragmentView != null) {
            mLoginFragmentView.onLoginSuccess();
        }
    }
}

模型界面

public interface LoginModelContract {
    interface OnLoginCompletedListener {
        void onUsernameError();
        void onPasswordError();
        void onSuccess();
    }
    void login(String username, String password, OnLoginCompletedListener onLoginCompletedListener);
}

模型实现

public class LoginModelImp implements LoginModelContract {
    /* Testing Valid username and passwords */
    private static String validUsername = "steve";
    private static String validPassword = "1234";

    @Override
    public void login(final String username,
                      final String password,
                      final OnLoginCompletedListener onLoginCompletedListener) {

        boolean hasSuccess = true;
        if(TextUtils.isEmpty(username) || !username.equals(validUsername)) {
        /* TEST onUsernameError() */
            onLoginCompletedListener.onUsernameError();
            hasSuccess = false;
        }

        if(TextUtils.isEmpty(password) || !password.equals(validPassword)) {
        /* TEST onPasswordError() */
            onLoginCompletedListener.onPasswordError();
            hasSuccess = false;
        }

        if(hasSuccess) {
        /* TEST onSuccess() */
            onLoginCompletedListener.onSuccess();
        }
    }
}

使用 Mockito 进行 JUnit4 测试

public class LoginPresenterImpTest {
    private LoginFragmentViewContract mMockViewContract;
    private LoginModelContract mMockModelContract;
    private LoginModelContract.OnLoginCompletedListener mMockOnLoginCompletedListener;
    private LoginPresenterContract<LoginFragmentViewContract> mLoginPresenterContract;

    @Before
    public void setUp() throws Exception {
        mMockViewContract = Mockito.mock(LoginFragmentViewContract.class);
        mMockModelContract = Mockito.mock(LoginModelContract.class);
        mMockOnLoginCompletedListener = Mockito.mock(LoginModelContract.OnLoginCompletedListener.class);
        mLoginPresenterContract = new LoginPresenterImp(mMockModelContract);
        mLoginPresenterContract.attachView(mMockViewContract);
    }

    @Test
    public void shouldSuccessWithValidCredentials() {
        when(mMockViewContract.getUsername()).thenReturn("steve");
        when(mMockViewContract.getPassword()).thenReturn("1234");

        mLoginPresenterContract.validateCredentials();

        verify(mMockViewContract, times(1)).getUsername();
        verify(mMockViewContract, times(1)).getPassword();

        verify(mMockOnLoginCompletedListener, times(1)).onSuccess();

        verify(mMockOnLoginCompletedListener, never()).onPasswordError();
        verify(mMockOnLoginCompletedListener, never()).onUsernameError();
    }
}

有什么方法可以测试这个实现吗？

非常感谢您的任何建议，

Answer 1

我可能没有理解你的意思，但你试过使用 PowerMock 吗？

您需要以下依赖项：

测试编译"org.powermock:powermock-module-junit4:1.6.5"
测试编译 "org.powermock:powermock-module-junit4-rule:1.6.5"
测试编译"org.powermock:powermock-api-mockito:1.6.5"
测试编译"org.powermock:powermock-classloading-xstream:1.6.5"

然后这样使用：

@PowerMockIgnore({ "org.mockito.*", "android.*" })
@PrepareForTest(DownloadPresenterContract.Events.class)
public class DownloadModelTest {

    @Rule
    public PowerMockRule rule = new PowerMockRule();

    private DownloadPresenterContract.Events mockEvents;

    @Before
    public void setUp() throws Exception {
         this.mockEvents = PowerMockito.spy(new DownloadPresenterContract.Events());

         PowerMockito.whenNew(DownloadPresenterContract.Events.class)
                     .withNoArguments()
                     .thenReturn(this.mockEvents); 
    }

    @Test
    public void testStaticMocking() {

         //Do your logic, which should trigger mockEvents actions

         Mockito.verify(this.mockEvents, Mockito.times(1)).onDownloadSuccess();
         //Or use this:
         //PowerMockito.verifyPrivate(this.mockEvents, times(1)).invoke("onDownloadSuccess", "someParam");
}

}

Answer 2

测试 class LoginPresenterImpTest 是关于 LoginPresenterImp class 的测试，它应该只使用它的实际实现和它的合作者的模拟。 class LoginModelContract.OnLoginCompletedListener 是 LoginModelImp 的合作者，因此在 LoginPresenterImp 的精心设计的纯单元测试中，像您一样，从未调用它是完全正常的. 我提出的解决方案是单独测试LoginModelImp：

public class LoginModelImpTest {

    private LoginModelContract.OnLoginCompletedListener mMockOnLoginCompletedListener;
    private LoginModelImp loginModelImp;

    @Before
    public void setUp() throws Exception {
        mMockOnLoginCompletedListener = Mockito.mock(LoginModelContract.OnLoginCompletedListener.class);
        loginModelImp = new LoginModelImp();
    }

    @Test
    public void shouldSuccessWithValidCredentials() {

        loginModelImp.login("steve", "1234", mMockOnLoginCompletedListener);;

        verify(mMockOnLoginCompletedListener, times(1)).onSuccess();

        verify(mMockOnLoginCompletedListener, never()).onPasswordError();
        verify(mMockOnLoginCompletedListener, never()).onUsernameError();
    }
}

或者，您必须在 LoginPresenterImpTest 中使用 LoginModelImp 的实际实现并监视您的侦听器（即演示者本身）或配置模拟以使它们调用侦听器.这是一个例子，但我不会使用这个：

public class LoginPresenterImpTest {
    private LoginFragmentViewContract mMockViewContract;
    private LoginModelContract mModelContract;
    private LoginModelContract.OnLoginCompletedListener mMockOnLoginCompletedListener;
    private LoginPresenterContract<LoginFragmentViewContract> mLoginPresenterContract;

    @Before
    public void setUp() throws Exception {
        mMockViewContract = Mockito.mock(LoginFragmentViewContract.class);
        mModelContract = new LoginModelImp();
        LoginPresenterImp spyPresenterImp = Mockito.spy(new LoginPresenterImp(mModelContract));
        mLoginPresenterContract = spyPresenterImp;
        mMockOnLoginCompletedListener = spyPresenterImp;
        mLoginPresenterContract.attachView(mMockViewContract);
    }

    @Test
    public void shouldSuccessWithValidCredentials() {
        when(mMockViewContract.getUsername()).thenReturn("steve");
        when(mMockViewContract.getPassword()).thenReturn("1234");

        mLoginPresenterContract.validateCredentials();

        verify(mMockViewContract, times(1)).getUsername();
        verify(mMockViewContract, times(1)).getPassword();

        verify(mMockOnLoginCompletedListener, times(1)).onSuccess();

        verify(mMockOnLoginCompletedListener, never()).onPasswordError();
        verify(mMockOnLoginCompletedListener, never()).onUsernameError();
    }
}

Answer 3

我认为因为你在嘲笑 LoginModelContract 和 OnLoginCompletedListener 你不能断言 onUsernameError、onPasswordError 和 onSuccess 实际上被调用了，因为通过模拟 LoginModelContract，"real" 登录方法（应该调用这些方法）将不会被执行，而只会调用模拟的方法。您可以使用以下内容触发这些方法：

Mockito.doAnswer(new Answer<Void>() {
    @Override
    public Void answer(InvocationOnMock invocation) throws Throwable {
        Object[] args = invocation.getArguments();
        OnLoginCompletedListener listener = (OnLoginCompletedListener) args[2];
        listener.onUsernameError();
        return null;
    }
}).when(mMockModelContract).login(anyString(), anyString(), any(OnLoginCompletedListener.class)).thenAnswer();

但是这样的测试毫无意义，因为您明确调用了您要测试的内容。

在我看来，只测试 LoginModelContract 而没有 LoginFragmentViewContract 和 LoginPresenterContract 会更有意义。类似于：

public class LoginPresenterImpTest {
    private LoginModelContract mMockModelContract;
    private LoginModelContract.OnLoginCompletedListener mMockOnLoginCompletedListener;

    @Before
    public void setUp() throws Exception {
        mMockOnLoginCompletedListener = Mockito.mock(LoginModelContract.OnLoginCompletedListener.class);
        mMockModelContract = new LoginModelContract();
    }

    @Test
    public void shouldSuccessWithValidCredentials() {
        mMockModelContract.login("steve", "1234", mMockOnLoginCompletedListener);

        verify(mMockOnLoginCompletedListener, times(1)).onSuccess();

        verify(mMockOnLoginCompletedListener, never()).onPasswordError();
        verify(mMockOnLoginCompletedListener, never()).onUsernameError();
    }
}

Answer 4

这归结为用户故事和用例之间的区别。在这种情况下，您有 1 个用户故事（例如 "As a User, I want to Login, so I provide my Username and Password"），但实际上至少有 3 个用例：正确的 Username/Right 密码，正确的 Username/Wrong 密码，错误的 Username/Right密码等。作为一般的最佳实践，您希望测试与用例对应1:1，所以我建议这样：

 @Test
 public void shouldCompleteWithValidCredentials() {
    mMockModelContract.login("steve", "1234", 
                              mMockOnLoginCompletedListener);

    verify(mMockOnLoginCompletedListener, times(1)).onSuccess();     
 }

 @Test
 public void shouldNotCompleteWithInvalidUser() {
    mMockModelContract.login("wrong_user", "1234",
                               mMockOnLoginCompletedListener);
    verify(mMockOnLoginCompletedListener, 
                            times(1)).onUsernameError();      
 }

@Test
public void shouldNotCompleteWithInvalidPassword() {
    mMockModelContract.login("steve", "wrong_password", 
                         mMockOnLoginCompletedListener);
    verify(mMockOnLoginCompletedListener, times(1)).onPasswordError();
}

换句话说，对于测试 1，您正在尝试积极验证，当用户名和密码完成时，调用成功。对于测试 2，您正在验证调用 onUsernameError 的条件，对于测试 3，验证调用 onPasswordError 的条件。这三个都是要测试的有效事物，您想要验证它们是否被调用是正确的，但您需要将它们视为不同的用例。

为了完整起见，我将验证 Wrong_User/Wrong_Password 上发生的情况，并验证如果出现 N 次 Wrong_Password 情况会发生什么（您需要冻结帐户吗？）。

希望这对您有所帮助。祝你好运。

使用 mockito 和事件监听器进行单元测试 MVP

Unit Testing MVP using mockito with event listeners

android

unit-testing

junit4

mockito