Android Espresso。执行（单击（））等待按钮单击完成启动的任务

Question

我正在编写一个经过检测的Android测试。当我点击按钮sample_btn时，Task和DummyTask开始。当Task结束时，EditText sample_text变为可见，我可以在那里输入一些文字。

当我注意到以下事实时，我感到很惊讶。 onView(withId(R.id.sample_btn)).perform(click());等待Task和DummyTask完成。为什么呢？

MainActivity

package com.sample;

import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;

import java.lang.ref.WeakReference;

    public class MainActivity extends AppCompatActivity implements View.OnClickListener {

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            findViewById(R.id.sample_btn).setOnClickListener(this);

        }

        @Override
        public void onClick(final View v) {
            switch (v.getId()) {
            case R.id.sample_btn:
                Log.d("UnderstandIsDisplayed", "Before sample_btn click IN CODE");
                new Task(this).execute();
                new DummyTask().execute();
                Log.d("UnderstandIsDisplayed", "After sample_btn click IN CODE");
                break;
            }
        }

        private static class DummyTask extends AsyncTask<Void, Void, Void> {

            @Override
            protected Void doInBackground(final Void... params) {
                try {
                    Log.d("UnderstandIsDisplayed", "DummyTask doInBackground");
                    Thread.sleep(8000);
                    Log.d("UnderstandIsDisplayed", "DummyTask doInBackground done");
                } catch (InterruptedException e) {
                }
                return null;
            }
        }

        private static class Task extends AsyncTask<Void, Void, Void> {

            final WeakReference<MainActivity> mActivityWeakReference;

            Task(MainActivity activity) {
                mActivityWeakReference = new WeakReference<>(activity);
            }

            @Override
            protected Void doInBackground(final Void... params) {
                try {
                    Log.d("UnderstandIsDisplayed", "doInBackground");
                    Thread.sleep(4000);
                    Log.d("UnderstandIsDisplayed", "doInBackground done");
                } catch (InterruptedException e) {
                }
                return null;
            }

            @Override
            protected void onPostExecute(final Void aVoid) {
                super.onPostExecute(aVoid);
                MainActivity mainActivity = mActivityWeakReference.get();
                if (mainActivity != null) {
                    mainActivity.findViewById(R.id.sample_text).setVisibility(View.VISIBLE);
                    Log.d("UnderstandIsDisplayed", "sample_text VISIBLE");
                }
            }
        }

    }

MainActivityTest

public class MainActivityTest extends ActivityInstrumentationTestCase2<MainActivity> {

    private MainActivity mMainActivity;

    public MainActivityTest() {
        super(MainActivity.class);
    }

    @Override
    protected void setUp() throws Exception {
        super.setUp();
        injectInstrumentation(InstrumentationRegistry.getInstrumentation());
        mMainActivity = getActivity();

    }

    public void testFoo() {
        Log.d("UnderstandIsDisplayed", "Before sample_btn click");
        onView(withId(R.id.sample_btn)).perform(click());
        Log.d("UnderstandIsDisplayed", "After sample_btn click");
        // TODO: Wait for sample_text to become visible
        onView(withId(R.id.sample_text)).perform(typeText("sample_text"));

    }
}

activity_main.xml中

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    android:id="@+id/container"
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#336633"
    android:orientation="vertical"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.sample.MainActivity">

    <Button
        android:id="@+id/sample_btn"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="sample_btn"/>

    <EditText
        android:id="@+id/sample_text"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:visibility="gone"/>

</LinearLayout>

的build.gradle

apply plugin: 'com.android.application'

android {
    compileSdkVersion 23
    buildToolsVersion "24.0.1"

    defaultConfig {
        applicationId "com.sample"
        minSdkVersion 15
        targetSdkVersion 23
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner 'android.support.test.runner.AndroidJUnitRunner'

    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    testCompile 'junit:junit:4.12'
    compile 'com.android.support:appcompat-v7:23.0.1'
    androidTestCompile 'com.android.support.test.espresso:espresso-core:2.2.1'
}

这是我在运行应用程序时看到的内容：

09-07 12:09:02.623 22356-22356/com.sample D/UnderstandIsDisplayed: Before sample_btn click IN CODE
09-07 12:09:02.629 22356-22660/com.sample D/UnderstandIsDisplayed: doInBackground 1562
09-07 12:09:02.631 22356-22356/com.sample D/UnderstandIsDisplayed: After sample_btn click IN CODE
09-07 12:09:06.670 22356-22660/com.sample D/UnderstandIsDisplayed: doInBackground done
09-07 12:09:06.672 22356-22356/com.sample D/UnderstandIsDisplayed: sample_text VISIBLE
09-07 12:09:06.680 22356-22771/com.sample D/UnderstandIsDisplayed: DummyTask doInBackground 1563
09-07 12:09:14.721 22356-22771/com.sample D/UnderstandIsDisplayed: DummyTask doInBackground done

这是我在运行testFoo时看到的：

09-07 12:10:24.357 24892-24911/com.sample D/UnderstandIsDisplayed: testFoo = 1555
09-07 12:10:24.357 24892-24911/com.sample D/UnderstandIsDisplayed: Before sample_btn click
09-07 12:10:24.429 24892-24892/com.sample D/UnderstandIsDisplayed: Before sample_btn click IN CODE
09-07 12:10:24.431 24892-24954/com.sample D/UnderstandIsDisplayed: doInBackground 1563
09-07 12:10:24.431 24892-24892/com.sample D/UnderstandIsDisplayed: After sample_btn click IN CODE
09-07 12:10:28.465 24892-24954/com.sample D/UnderstandIsDisplayed: doInBackground done
09-07 12:10:28.469 24892-24892/com.sample D/UnderstandIsDisplayed: sample_text VISIBLE
09-07 12:10:28.472 24892-24936/com.sample D/UnderstandIsDisplayed: DummyTask doInBackground 1558
09-07 12:10:36.483 24892-24936/com.sample D/UnderstandIsDisplayed: DummyTask doInBackground done
09-07 12:10:36.702 24892-24911/com.sample D/UnderstandIsDisplayed: After sample_btn click

Answer 1

使用Espresso，您只能在测试环境下的应用内操作。这意味着Espresso用于执行任何操作需要在app的主线程上运行。它检查UI线程何时为idle()，如果不是，则等待UI线程再次空闲。

检查：http://dev.jimdo.com/2014/05/09/wait-for-it-a-deep-dive-into-espresso-s-idling-resources/

在某些情况下，它会产生Espressso IdlingResources错误，例如AppNotIdleState：https://developer.android.com/reference/android/support/test/espresso/AppNotIdleException.html

示例1＃：https://github.com/81813780/AVLoadingIndicatorView/issues/16

示例2＃：Espresso test fails after successful click and blocking for 60 seconds

要处理此问题，您可以创建自己的IdlingResource方法，以便在UI线程为Espresso时为idle说明。

检查：https://google.github.io/android-testing-support-library/docs/espresso/idling-resource/index.html

例如：http://blog.sqisland.com/2015/04/espresso-custom-idling-resource.html

如果无效，请尝试与Espresso另一个名为uiatomator的Google测试框架一起使用，这可能会帮助您解决此问题。

就我而言，编写自己的IdlingResources无效，但将Espresso与Robotium混合（不等待空闲的UI线程）和uiautomator完成了它的工作。

希望它会有所帮助

Answer 2

AsyncTask处理已融入UiControllerImpl.loopMainThreadUntilIdle()中的espresso框架。在大多数情况下，espresso处理一些开箱即用的背景工作非常方便。不幸的是，没有可用的解决方案来关闭任何提供的处理程序（UI线程同步，异步任务）。这使得测试进度指标或测试中断变得非常复杂。

espresso bug tracker中有一个未解决的问题，但它没有引起太多关注。