testImplementation "junit:junit:4.12"
testImplementation "org.mockito:mockito-core:2.7.1"

mPresenter = new NewsPresenter(mDataManager);
mPresenter.getNews();
mPresenter.attach(mView);
--> mView.showProgress(); // 在数据未加载完前加载进度条
--> mView.showNews(news);
--> mView.hideProgress(); // 在数据加载完后隐藏进度条

/**
 * Created by Xu on 2019/04/05.
 *
 * @author Xu
 */
public class NewsPresenterTest {
    @ClassRule
    public static final RxImmediateSchedulerRule schedulers = new RxImmediateSchedulerRule();

    @Mock
    private NewsContract.View view;
    @Mock
    protected DataManager mMockDataManager;
    private NewsPresenter newsPresenter;
    
    @Before
    public void setUp() {
        MockitoAnnotations.initMocks(this);
        newsPresenter = new NewsPresenter(mMockDataManager);
        newsPresenter.attach(view);
    }
    
    @Test
    public void getNewsAndLoadIntoView() {
        TencentNewsResultBean resultBean = new TencentNewsResultBean();
        resultBean.setData(new ArrayList<>());
        when(mMockDataManager.getNews()).thenReturn(Flowable.just(resultBean));

        newsPresenter.getNews();

        // 测试model是否有获取数据
        verify(mMockDataManager).getNews();

        // 测试view是否调用相应接口
        verify(view).showProgress();
        verify(view).showNews(anyList());
        verify(view).hideProgress();
    }

    @After
    public void tearDown() {
        newsPresenter.detach();
    }
}

/**
 * Created by Xu on 2019/04/05.
 *
 * @author Xu
 */
public class RxImmediateSchedulerRule implements TestRule {
    private Scheduler immediate = new Scheduler() {
        @Override
        public Disposable scheduleDirect(@NonNull Runnable run, long delay, @NonNull TimeUnit unit) {
            // this prevents StackOverflowErrors when scheduling with a delay
            return super.scheduleDirect(run, 0, unit);
        }

        @Override
        public Worker createWorker() {
            return new ExecutorScheduler.ExecutorWorker(Runnable::run);
        }
    };

    @Override
    public Statement apply(final Statement base, Description description) {
        return new Statement() {
            @Override
            public void evaluate() throws Throwable {
                RxJavaPlugins.setInitIoSchedulerHandler(scheduler -> immediate);
                RxJavaPlugins.setInitComputationSchedulerHandler(scheduler -> immediate);
                RxJavaPlugins.setInitNewThreadSchedulerHandler(scheduler -> immediate);
                RxJavaPlugins.setInitSingleSchedulerHandler(scheduler -> immediate);
                RxAndroidPlugins.setInitMainThreadSchedulerHandler(scheduler -> immediate);

                try {
                    base.evaluate();
                } finally {
                    RxJavaPlugins.reset();
                    RxAndroidPlugins.reset();
                }
            }
        };
    }
}

androidTestImplementation "androidx.test:runner:1.1.0"
androidTestImplementation "androidx.test:rules:1.1.0"
androidTestImplementation "androidx.test.espresso:espresso-core:3.0.2"
androidTestImplementation "androidx.test.espresso:espresso-contrib:3.0.2"
androidTestImplementation "androidx.test.espresso:espresso-intents:3.0.2"
androidTestImplementation "androidx.test.espresso.idling:idling-concurrent:3.0.2"
androidTestImplementation "androidx.test.espresso:espresso-idling-resource:3.0.2"

/**
 * Created by Xu on 2019/04/09.
 */
@RunWith(AndroidJUnit4.class)
@LargeTest
public class NewsDetailActivityTest {

    @Rule
    public ActivityTestRule<NewsDetailActivity> newsDetailActivityActivityTestRule =
            new ActivityTestRule<>(NewsDetailActivity.class, true, false);

    @Before
    public void setUp() {
        Intent intent = new Intent(InstrumentationRegistry.getInstrumentation().getTargetContext(), NewsDetailActivity.class);
        intent.putExtra(Constants.NEWS_URL, TestConstants.NEWS_DETAIL_ACTIVITY_TEST_URL);
        intent.putExtra(Constants.NEWS_IMG, TestConstants.NEWS_DETAIL_ACTIVITY_TEST_IMG);
        intent.putExtra(Constants.NEWS_TITLE, TestConstants.NEWS_DETAIL_ACTIVITY_TEST_TITLE);
        newsDetailActivityActivityTestRule.launchActivity(intent);
        IdlingRegistry.getInstance().register(newsDetailActivityActivityTestRule.getActivity().getCountingIdlingResource());
    }

    @Test
    public void showNewsDetail() {
        onView(withId(R.id.toolbar)).check(matches(isDisplayed()));
        onView(withId(R.id.iv_news_detail_pic)).check(matches(isDisplayed()));
        onView(withId(R.id.clp_toolbar)).check(matches(isDisplayed()));
        onView(withId(R.id.clp_toolbar)).check(matches(withCollapsingToolbarLayoutText(is(TestConstants.NEWS_DETAIL_ACTIVITY_TEST_TITLE))));
    }

    @After
    public void tearDown() {
        IdlingRegistry.getInstance().unregister(newsDetailActivityActivityTestRule.getActivity().getCountingIdlingResource());
    }
}

public class NewsDetailActivity extends AppCompatActivity {

    @BindView(R.id.iv_news_detail_pic)
    private ImageView ivNewsDetailPic;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_news);
        // 省略部分代码逻辑
        
        // 开始发起异步操作，App开始进入忙碌状态
        EspressoIdlingResource.increment();
        
        // 开始加载图片
        Glide.with(context).asBitmap().load(imgUrl).into(new GlideDrawableImageViewTarget(mAvatar) {
            @Override
            public void onResourceReady(@NonNull Bitmap resource, @Nullable Transition<? super Bitmap> transition) {
                super.onResourceReady(resource, transition);
                // 异步操作结束，将App设置成空闲状态
                if (!EspressoIdlingResource.getIdlingResource().isIdleNow()) {
                    EspressoIdlingResource.decrement();
                }
            }
        });
    }
    
    // 省略代码
    
    @VisibleForTesting
    public IdlingResource getCountingIdlingResource() {
        return EspressoIdlingResource.getIdlingResource();
    }
}

public class EspressoIdlingResource {
    private static final String RESOURCE = "GLOBAL";

    // Espresso 提供了一个实现好的 CountingIdlingResource 类
    // 如果没有特别需求的话，直接使用它即可
    private static CountingIdlingResource countingIdlingResource = new CountingIdlingResource(RESOURCE);

    public static void increment() {
        countingIdlingResource.increment();
    }

    public static void decrement() {
        countingIdlingResource.decrement();
    }

    public static IdlingResource getIdlingResource() {
        if (countingIdlingResource == null) {
            countingIdlingResource = new CountingIdlingResource(RESOURCE);
        }
        return countingIdlingResource;
    }

}

public static Matcher<View> withCollapsingToolbarLayoutText(Matcher<String> stringMatcher) {
    return new BoundedMatcher<View, CollapsingToolbarLayout>(CollapsingToolbarLayout.class) {
        @Override
        public void describeTo(Description description) {
            description.appendText("with CollapsingToolbarLayout title: ");
            stringMatcher.describeTo(description);
        }

        @Override
        protected boolean matchesSafely(CollapsingToolbarLayout collapsingToolbarLayout) {
            return stringMatcher.matches(collapsingToolbarLayout.getTitle());
        }
    };
}