Android UI测试崩溃，但应用运行良好

Question

所以我正在创建一个使用这个库https://github.com/OmerUygurOzer/Knit（我创建的东西）的示例项目。

问题是测试不会随之运行。不知道为什么。该应用程序本身工作正常。但是当我运行测试时，它在错误的行上就会在Application类中调用Knit.init(this);。

这是logcat

02-13 20:46:20.471 23727-23727/com.omerozer.knitmvpexample W/System.err: java.lang.NoSuchMethodException: <init> [interface com.omerozer.knit.InternalModel]
02-13 20:46:20.472 23727-23727/com.omerozer.knitmvpexample W/System.err:     at java.lang.Class.getConstructor(Class.java:531)
02-13 20:46:20.472 23727-23727/com.omerozer.knitmvpexample W/System.err:     at java.lang.Class.getConstructor(Class.java:495)
02-13 20:46:20.472 23727-23727/com.omerozer.knitmvpexample W/System.err:     at com.omerozer.knit.KnitClassLoader.getViewToPresenterConstructor(KnitClassLoader.java:64)
02-13 20:46:20.472 23727-23727/com.omerozer.knitmvpexample W/System.err:     at com.omerozer.knit.KnitClassLoader.getViewToPresenterMap(KnitClassLoader.java:79)
02-13 20:46:20.472 23727-23727/com.omerozer.knitmvpexample W/System.err:     at com.omerozer.knit.KnitClassLoader.<init>(KnitClassLoader.java:23)
02-13 20:46:20.472 23727-23727/com.omerozer.knitmvpexample W/System.err:     at com.omerozer.knit.Knit.init(Knit.java:28)
02-13 20:46:20.472 23727-23727/com.omerozer.knitmvpexample W/System.err:     at com.omerozer.knitmvpexample.MVPApp.onCreate(MVPApp.java:16)
02-13 20:46:20.472 23727-23727/com.omerozer.knitmvpexample W/System.err:     at android.app.Instrumentation.callApplicationOnCreate(Instrumentation.java:1012)
02-13 20:46:20.472 23727-23727/com.omerozer.knitmvpexample W/System.err:     at android.support.test.runner.MonitoringInstrumentation.callApplicationOnCreate(MonitoringInstrumentation.java:382)
02-13 20:46:20.472 23727-23727/com.omerozer.knitmvpexample W/System.err:     at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4553)
02-13 20:46:20.472 23727-23727/com.omerozer.knitmvpexample W/System.err:     at android.app.ActivityThread.access$1500(ActivityThread.java:151)
02-13 20:46:20.472 23727-23727/com.omerozer.knitmvpexample W/System.err:     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1364)
02-13 20:46:20.472 23727-23727/com.omerozer.knitmvpexample W/System.err:     at android.os.Handler.dispatchMessage(Handler.java:102)
02-13 20:46:20.472 23727-23727/com.omerozer.knitmvpexample W/System.err:     at android.os.Looper.loop(Looper.java:135)
02-13 20:46:20.472 23727-23727/com.omerozer.knitmvpexample W/System.err:     at android.app.ActivityThread.main(ActivityThread.java:5254)
02-13 20:46:20.472 23727-23727/com.omerozer.knitmvpexample W/System.err:     at java.lang.reflect.Method.invoke(Native Method)
02-13 20:46:20.472 23727-23727/com.omerozer.knitmvpexample W/System.err:     at java.lang.reflect.Method.invoke(Method.java:372)
02-13 20:46:20.472 23727-23727/com.omerozer.knitmvpexample W/System.err:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
02-13 20:46:20.472 23727-23727/com.omerozer.knitmvpexample W/System.err:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
02-13 20:46:20.473 23727-23727/com.omerozer.knitmvpexample E/InstrumentationResultPrinter: Failed to mark test No Tests as finished after process crash
02-13 20:46:20.473 23727-23727/com.omerozer.knitmvpexample E/MonitoringInstr: Exception encountered by: com.omerozer.knitmvpexample.MVPApp@3a68f1a5. Dumping thread state to outputs and pining for the fjords.
                                                                              java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Object java.lang.reflect.Constructor.newInstance(java.lang.Object[])' on a null object reference
                                                                                  at com.omerozer.knit.KnitClassLoader.getViewToPresenterMap(KnitClassLoader.java:79)
                                                                                  at com.omerozer.knit.KnitClassLoader.<init>(KnitClassLoader.java:23)
                                                                                  at com.omerozer.knit.Knit.init(Knit.java:28)
                                                                                  at com.omerozer.knitmvpexample.MVPApp.onCreate(MVPApp.java:16)
                                                                                  at android.app.Instrumentation.callApplicationOnCreate(Instrumentation.java:1012)
                                                                                  at android.support.test.runner.MonitoringInstrumentation.callApplicationOnCreate(MonitoringInstrumentation.java:382)
                                                                                  at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4553)
                                                                                  at android.app.ActivityThread.access$1500(ActivityThread.java:151)
                                                                                  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1364)
                                                                                  at android.os.Handler.dispatchMessage(Handler.java:102)
                                                                                  at android.os.Looper.loop(Looper.java:135)
                                                                                  at android.app.ActivityThread.main(ActivityThread.java:5254)
                                                                                  at java.lang.reflect.Method.invoke(Native Method)
                                                                                  at java.lang.reflect.Method.invoke(Method.java:372)
                                                                                  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)

错误信息是这样的：

Started running tests
Test running failed: Instrumentation run failed due to   java.lang.NullPointerException

好像测试环境找不到init方法？这对我没有意义。

这是gradle设置。

    apply plugin: 'com.android.application'

android {
    compileSdkVersion 26
    defaultConfig {
        applicationId "com.omerozer.knitmvpexample"
        minSdkVersion 15
        targetSdkVersion 26
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'com.android.support:appcompat-v7:26.1.0'
    implementation 'com.android.support.constraint:constraint-layout:1.0.2'
    implementation 'com.android.support:design:26.1.0'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'com.android.support.test:runner:1.0.1'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.1'

    androidTestImplementation 'com.github.OmerUygurOzer.knit:knitlib:v1.0.2'
    androidTestAnnotationProcessor 'com.github.OmerUygurOzer.knit:knitprocessor:v1.0.2'

    implementation 'com.github.OmerUygurOzer.knit:knitlib:v1.0.2'
    annotationProcessor 'com.github.OmerUygurOzer.knit:knitprocessor:v1.0.2'

    androidTestCompile 'com.android.support.test.espresso:espresso-core:3.0.1'
    androidTestCompile 'com.android.support.test:runner:1.0.1'

}

Answer 1

这正是Espresso中发生的事情。

Android JUnit runner在运行应用程序的同一进程中运行。如果您的应用程序中有运行时异常（即NullPointerException），它将破坏整个Instrumentation过程。

我手动运行应用程序时注意到了这一点。它运行良好，在运行仪器测试时，但在某些时候，仪表刚刚崩溃。

经过进一步调查后，我注意到在我们的应用程序中使用的模块中有一个NullPointerException。

如果你想避免仪器崩溃的情况，你可以使用Android Test Orchestrator（查看演示文稿here）。以这种方式运行测试，您将遇到孤立的崩溃。

如果您可以修复代码中发生的关键异常，那就去做吧:-)