应用程序在 UI 测试期间启动后关闭

Question

我正在尝试使用 espresso 在 android 应用程序上运行 UI 测试，但是当我在移动设备或模拟器上运行测试时，应用程序会打开并突然关闭，速度很快，甚至在测试运行之前也是如此。

这并不是应用程序崩溃，它只是在运行测试时一打开就关闭。我不确定在引发这种行为的测试配置中缺少什么。

这是我的 gradle 文件

apply plugin: 'com.android.application'
apply plugin: 'realm-android'

android {
compileSdkVersion 25
buildToolsVersion '25.0.3'

defaultConfig {
    applicationId "com.test1"
    minSdkVersion 14
    targetSdkVersion 25
    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-v7:25.3.1'
compile 'com.android.support:support-v4:25.3.1'
compile 'com.android.support:recyclerview-v7:25.3.1'
compile 'com.android.support:cardview-v7:25.3.1'
compile 'com.android.support:design:25.3.1'
compile 'com.squareup.picasso:picasso:2.5.2'
compile 'jp.wasabeef:picasso-transformations:2.1.2'
compile 'com.google.firebase:firebase-database:9.4.0'
compile 'com.google.firebase:firebase-auth:9.4.0'
compile 'com.google.firebase:firebase-messaging:9.4.0'
compile 'com.google.android.gms:play-services-location:9.4.0'
compile 'com.google.android.gms:play-services-places:9.4.0'
compile 'com.squareup.retrofit2:retrofit:2.3.0'
compile 'com.squareup.retrofit2:converter-gson:2.1.0'
androidTestCompile ('com.android.support.test:runner:1.0.1') {
    exclude module: 'support-annotations'
}
androidTestCompile ('com.android.support.test:rules:1.0.1') {
    exclude module: 'support-annotations'
}
androidTestCompile ('com.android.support.test.espresso:espresso-intents:3.0.1') {
    exclude module: 'support-annotations'
}
androidTestCompile ('com.android.support.test.espresso:espresso-web:3.0.1') {
    exclude module: 'support-annotations'
}
androidTestCompile ('com.android.support.test.espresso:espresso-core:3.0.1') {
    exclude module: 'support-annotations'
}
}

apply plugin: 'com.google.gms.google-services'

这是我的测试

@RunWith(AndroidJUnit4.class)
public class PAC4Testing {


@Rule
public ActivityTestRule<BookListActivity> mActivityRule = new ActivityTestRule<>(
        BookListActivity.class);


@Test
public void checkLoadedList() {
   if (getRVcount() > 0){
        assertEquals(9,getRVcount());
    }
}

private int getRVcount(){
    RecyclerView recyclerView = (RecyclerView) mActivityRule.getActivity().findViewById(R.id.book_list);
    return recyclerView.getAdapter().getItemCount();
}

@Test
public void checkMenuOpened() {

}

@Test
public void checkLoadedWebViewFromDetail() {

}
}

谢谢！

编辑这些是日志，运行测试时出现错误，因为应用程序关闭，测试在屏幕上找不到任何内容。

java.lang.NullPointerException: Attempt to invoke virtual method 'int 

android.support.v7.widget.RecyclerView$Adapter.getItemCount()' on a null object reference
at PAC4Testing.getRVcount(PAC4Testing.java:34)
at PAC4Testing.checkLoadedList(PAC4Testing.java:27)
at java.lang.reflect.Method.invoke(Native Method)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at android.support.test.rule.ActivityTestRule$ActivityStatement.evaluate(ActivityTestRule.java:433)
at org.junit.rules.RunRules.evaluate(RunRules.java:20)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.junit.runners.Suite.runChild(Suite.java:128)
at org.junit.runners.Suite.runChild(Suite.java:27)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
at org.junit.runner.JUnitCore.run(JUnitCore.java:115)
at android.support.test.internal.runner.TestExecutor.execute(TestExecutor.java:58)
at android.support.test.runner.AndroidJUnitRunner.onStart(AndroidJUnitRunner.java:375)
at android.app.Instrumentation$InstrumentationThread.run(Instrumentation.java:1886)

Answer 1

错误清楚地表明getRVcount() 中的recyclerView.getAdapter() 调用正在返回null。这是因为即使您确实从RecyclerView recyclerView = (RecyclerView) mActivityRule.getActivity().findViewById(R.id.book_list); 获得了视图，但您获得的 recyclerview 与类中的不同，因为它是新的，并且没有与之关联的适配器或 LayoutManagers。因此，您无法在适配器上调用getItemCount()。

我不确定你究竟想在这里测试什么，因为你还没有发布课程的代码，但这里有几个链接你可能想看看，看看它们是否对你有任何帮助https://spin.atomicobject.com/2016/04/15/espresso-testing-recyclerviews/ 和 http://alexander-thiele.blogspot.in/2016/01/espresso-ui-tests-and-recyclerview.html

Answer 2

您不应该在测试执行期间从Instrumentation 线程查询 UI 的状态，因为它不提供与主线程的任何同步。

如果需要查询状态，您应该使用 espresso ViewMatchers 或实现自己的匹配器。 Espresso 具有内置的主线程同步功能，可确保在返回结果之前对 UI 的所有更新都已完成。

下面是返回项数的匹配器示例：

    fun hasCount(expectedCount: Int): Matcher<View> =
        object : BoundedMatcher<View, RecyclerView>(RecyclerView::class.java) {
            var actualCount = -1

            override fun describeTo(description: Description) {
                if (actualCount > -1) {
                    description.apply {
                        appendText("$expectedCount number of items in RecyclerView")
                        appendText("\n But $actualCount")
                    }
                }
            }

            override fun matchesSafely(recyclerView: RecyclerView): Boolean {
                actualCount = recyclerView.adapter.itemCount

                return actualCount == expectedCount
            }
        }

而它的用法是这样的：

onView(withId(R.id.recyclerView)).check(matches(hasCount(5)))