使用仪器和 JUnit4 测试重新创建 Android Activity

Question

我想为重新创建编写测试 activity。执行旋转是可选的。

我希望 Google 使用最新版本的测试框架 "blessed" 编写测试。我是编写测试的新手，所以我想学习基本的、主流的、支持良好的工具。当我掌握基础知识时，任何第 3 方测试框架都可以。而且由于我想测试非常基本的、经常出现的场景，基本的工具应该就足够了，对吧？

最小测试代码：

public class MainActivity extends AppCompatActivity {

    static int creationCounter = 0;
    Integer instanceId;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        ++creationCounter;
        instanceId = new Integer(creationCounter);
        Log.d("TEST", "creating activity " + this + ", has id " + instanceId);
    }
}

并测试class：

@RunWith(AndroidJUnit4.class)
public class ExampleInstrumentedTest {

    @Rule
    public ActivityTestRule<MainActivity> mActivityTestRule = new ActivityTestRule<>(MainActivity.class);

    @Test
    public void useAppContext() throws Exception {

        MainActivity activity1 = mActivityTestRule.getActivity();
        int act1 = activity1.instanceId.intValue();
        int counter1 = MainActivity.creationCounter;
        assertEquals(1, counter1);
        assertEquals(1, act1);


        Log.d("TEST", "requesting rotation");
        // method 1
         activity1.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
        // method 2 //https://gist.github.com/nbarraille/03e8910dc1d415ed9740#file-orientationchangeaction-java
        // onView(isRoot()).perform(orientationLandscape());

        getInstrumentation().waitForIdleSync(); // I thought this should suffice
        // How to do this?
        //somehowRefreshActivityInstanceInsideTestRule();

        MainActivity activity2 = mActivityTestRule.getActivity();
        int act2 = activity2.instanceId.intValue();
        int counter2 = MainActivity.creationCounter;
        Log.d("TEST", "newly acquired activity " + activity2 + " has id " + act2 + "/" + counter2);

        assertEquals(2, counter2);
        assertEquals(2, act2);
    }
}

以上代码（方法 1 或 2）给出 logcat:

D/ActivityTestRule: Launching activity example.com.rotationtest.MainActivity
D/TEST: creating activity example.com.rotationtest.MainActivity@47404a3, has id 1
D/TEST: requesting rotation
D/TEST: creating activity example.com.rotationtest.MainActivity@169887e, has id 2
D/TEST: newly acquired activity example.com.rotationtest.MainActivity@47404a3 has id 1/2
I/TestRunner: failed: useAppContext(example.com.rotationtest.ExampleInstrumentedTest)
I/TestRunner: ----- begin exception -----
I/TestRunner: java.lang.AssertionError: expected:<2> but was:<1>

我的诊断，如有错误请指正：

activity1.setRequestedOrientation 导致在其他线程中创建新的 activity。我希望它能收到合适的捆绑包
getInstrumentation().waitForIdleSync();导致测试等到新的activity被创建
mActivityTestRule.getActivity();仍然是 returns 旧的 activity 实例。
我需要一些方法来刷新 activity 测试规则中保存的实例，释放之前保存的一个实例。

我用旧版本的测试框架找到了答案：Instrumentation test for Android - How to receive new Activity after orientation change?

mActivity.setRequestedOrientation(
    ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
mActivity.finish();
setActivity(null);
mActivity = getActivity();
getInstrumentation().waitForIdleSync();

但是我不知道怎么翻译成新版本。

编辑：

以上两种方法都使 activity 处于销毁状态：assertFalse(mActivityTestRule.getActivity().isDestroyed());失败。

我发现了另一种方法 (Destroy and restart Activity with Testing Support Library) 可以重新创建 activity 实例，但不会通过 onSaveInstanceState

保持其状态

Answer 1

我终于在这里找到了可行的解决方案：Get Current Activity in Espresso android

适应我的需求后代码如下所示：

public class CurrentActivityTestRule<T extends Activity> extends ActivityTestRule<T> {
    public CurrentActivityTestRule(Class<T> activityClass) {
        super(activityClass, false);
    }

    public CurrentActivityTestRule(Class<T> activityClass, boolean initialTouchMode) {
        super(activityClass, initialTouchMode, true);
    }

    public CurrentActivityTestRule(Class<T> activityClass, boolean initialTouchMode, boolean launchActivity) {
        super(activityClass, initialTouchMode, launchActivity);
    }

    public T getCurrentActivity() {
        getInstrumentation().waitForIdleSync();
        final Activity[] activity = new Activity[1];
        getInstrumentation().runOnMainSync(new Runnable() {
            @Override
            public void run() {
                java.util.Collection<Activity> activities = ActivityLifecycleMonitorRegistry.getInstance().getActivitiesInStage(Stage.RESUMED);
                activity[0] = Iterables.getOnlyElement(activities);
            }});
        T current = (T) activity[0];
        return current;
    }
}

并且是这样使用的：

onView(isRoot()).perform(orientationLandscape());
Activity oldActivityInstance = mActivityTestRule.getActivity();
Activity currentActivityInstance = mActivityTestRule.getCurrentActivity();

我使用的是库版本：

androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
    exclude group: 'com.android.support', module: 'support-annotations'
})
androidTestCompile('com.android.support.test:runner:0.5', {
    exclude group: 'com.android.support', module: 'support-annotations'
})

Answer 2

当前版本的 android.test.rule 解决了这个问题。您只需要在调用 activityTestRule.getActivity()

之前调用 InstrumentationRegistry.getInstrumentation().waitForIdleSync()

Answer 3

@MateuszL 的解决方案现在仍然适用于 androidx 测试编排器和 Kotlin，以防此版本对任何人有帮助：

import androidx.test.espresso.core.internal.deps.guava.collect.Iterables
import androidx.test.platform.app.InstrumentationRegistry.getInstrumentation
import androidx.test.rule.ActivityTestRule
import androidx.test.runner.lifecycle.ActivityLifecycleMonitorRegistry
import androidx.test.runner.lifecycle.Stage

class CurrentActivityTestRule<T : Activity> : ActivityTestRule<T> {

    val currentActivity: T
        get() {
            getInstrumentation().waitForIdleSync()
            val activity = arrayOfNulls<Activity>(1)
            getInstrumentation().runOnMainSync(Runnable {
                val activities = ActivityLifecycleMonitorRegistry.getInstance().getActivitiesInStage(Stage.RESUMED)
                activity[0] = Iterables.getOnlyElement(activities)
            })
            @Suppress("UNCHECKED_CAST")
            return activity[0] as T
        }

    constructor(activityClass: Class<T>) : super(activityClass, false)

    constructor(activityClass: Class<T>, initialTouchMode: Boolean) : super(activityClass, initialTouchMode, true)

    constructor(activityClass: Class<T>, initialTouchMode: Boolean, launchActivity: Boolean) : super(
        activityClass,
        initialTouchMode,
        launchActivity
    )
}

...并且在 Kotlin 中是这样使用的，例如，如果我们知道此时在测试中当前 activity 应该是 RegistrationActivity 并且我们需要在一个过程中直接访问它的功能之一集成测试：

@Suppress("CAST_NEVER_SUCCEEDS")
private fun getRegistrationActivity()= activityTestRule.currentActivity as RegistrationActivity

使用仪器和 JUnit4 测试重新创建 Android Activity

Test recreating Android Activity using instrumentation and JUnit4

java

instrumentation

android

automated-tests

android-junit