Develop Reference

Why do tests fail when executed as a class?

I have a series of tests separated into classes. The tests run properly when run individually or when run as a whole package. Most classes also run properly when executed as a class, but there is one class that fails to execute with the following error:
java.lang.RuntimeException: Delegate runner 'org.robolectric.RobolectricTestRunner' for AndroidJUnit4 could not be loaded.
at androidx.test.ext.junit.runners.AndroidJUnit4.throwInitializationError(AndroidJUnit4.java:92)
at androidx.test.ext.junit.runners.AndroidJUnit4.loadRunner(AndroidJUnit4.java:82)
at androidx.test.ext.junit.runners.AndroidJUnit4.loadRunner(AndroidJUnit4.java:51)
at androidx.test.ext.junit.runners.AndroidJUnit4.<init>(AndroidJUnit4.java:46)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at org.junit.internal.builders.AnnotatedBuilder.buildRunner(AnnotatedBuilder.java:104)
at org.junit.internal.builders.AnnotatedBuilder.runnerForClass(AnnotatedBuilder.java:86)
at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:59)
at org.junit.internal.builders.AllDefaultPossibilitiesBuilder.runnerForClass(AllDefaultPossibilitiesBuilder.java:26)
at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:59)
at org.junit.internal.requests.ClassRequest.getRunner(ClassRequest.java:33)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:49)
at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33)
at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:230)
at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:58)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at androidx.test.ext.junit.runners.AndroidJUnit4.loadRunner(AndroidJUnit4.java:72)
... 16 more
Caused by: java.lang.NoClassDefFoundError: androidx/test/rule/ActivityTestRule
at java.lang.Class.getDeclaredMethods0(Native Method)
at java.lang.Class.privateGetDeclaredMethods(Class.java:2701)
at java.lang.Class.getDeclaredMethods(Class.java:1975)
at org.junit.internal.MethodSorter.getDeclaredMethods(MethodSorter.java:54)
at org.junit.runners.model.TestClass.scanAnnotatedMembers(TestClass.java:65)
at org.junit.runners.model.TestClass.<init>(TestClass.java:57)
at org.junit.runners.ParentRunner.createTestClass(ParentRunner.java:88)
at org.junit.runners.ParentRunner.<init>(ParentRunner.java:83)
at org.junit.runners.BlockJUnit4ClassRunner.<init>(BlockJUnit4ClassRunner.java:65)
at org.robolectric.internal.SandboxTestRunner.<init>(SandboxTestRunner.java:56)
at org.robolectric.RobolectricTestRunner.<init>(RobolectricTestRunner.java:92)
... 21 more
Caused by: java.lang.ClassNotFoundException: androidx.test.rule.ActivityTestRule
at java.net.URLClassLoader.findClass(URLClassLoader.java:382)
at java.lang.ClassLoader.loadClass(ClassLoader.java:419)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:352)
at java.lang.ClassLoader.loadClass(ClassLoader.java:352)
... 32 more
The problem only appears in this specific class and when the tests are run on the class, not individually or as a package.
I have verified that only androidx libraries are being used, that rules are setup properly and that the roboelectric dependency is included as per other answers in this forum.
Has anyone had a similar problem or has any suggestions to fix this issue?
Note: I have tried recreating the issue in a small example code, but haven't been able to. I also can't post the code that fails due to proprietary reasons.

The problem was due to having public methods in the test class that were not annotated with #Test. The solution I used was adding #Ignore and #Test annotations to the method. ie:
#Ignore #Test fun someUnImplementedTest() { }
Adding only #Test works as well, but it will run the test and mark it as passed allowing you to forget that it's not yet implemented.

Flutter - no class definition found exception on upgrading android native build to flutter build

I'm updating my Android native app to flutter. I've created a new project in flutter code base. Ive updated my version code and name but this exception im getting while installing flutter release APK over Android Native APK. Here is the exception
Class not found when unmarshalling: com.android.packageinstaller.InstallFlowAnalytics
java.lang.ClassNotFoundException: com.android.packageinstaller.InstallFlowAnalytics
at java.lang.Class.classForName(Native Method)
at java.lang.Class.forName(Class.java:324)
at android.os.Parcel.readParcelableCreator(Parcel.java:2404)
at android.os.Parcel.readParcelable(Parcel.java:2358)
at android.os.Parcel.readValue(Parcel.java:2264)
at android.os.Parcel.readArrayMapInternal(Parcel.java:2614)
at android.os.BaseBundle.unparcel(BaseBundle.java:221)
at android.os.BaseBundle.getString(BaseBundle.java:920)
at android.content.Intent.getStringExtra(Intent.java:6183)
at com.android.server.am.ActivityStackSupervisor.startActivityLocked(ActivityStackSupervisor.java:2695)
at com.android.server.am.ActivityStackSupervisor.startActivityMayWait(ActivityStackSupervisor.java:2157)
at com.android.server.am.ActivityManagerService.startActivityAsUser(ActivityManagerService.java:6336)
at com.android.server.am.ActivityManagerService.startActivity(ActivityManagerService.java:6114)
at android.app.ActivityManagerNative.onTransact(ActivityManagerNative.java:170)
at com.android.server.am.ActivityManagerService.onTransact(ActivityManagerService.java:3986)
at android.os.Binder.execTransact(Binder.java:453)
Caused by: java.lang.ClassNotFoundException: com.android.packageinstaller.InstallFlowAnalytics
at java.lang.Class.classForName(Native Method)
at java.lang.BootClassLoader.findClass(ClassLoader.java:781)
at java.lang.BootClassLoader.loadClass(ClassLoader.java:841)
at java.lang.ClassLoader.loadClass(ClassLoader.java:469)
at java.lang.Class.classForName(Native Method) 
at java.lang.Class.forName(Class.java:324) 
at android.os.Parcel.readParcelableCreator(Parcel.java:2404) 
at android.os.Parcel.readParcelable(Parcel.java:2358) 
at android.os.Parcel.readValue(Parcel.java:2264) 
at android.os.Parcel.readArrayMapInternal(Parcel.java:2614) 
at android.os.BaseBundle.unparcel(BaseBundle.java:221) 
at android.os.BaseBundle.getString(BaseBundle.java:920) 
at android.content.Intent.getStringExtra(Intent.java:6183) 
at com.android.server.am.ActivityStackSupervisor.startActivityLocked(ActivityStackSupervisor.java:2695) 
at com.android.server.am.ActivityStackSupervisor.startActivityMayWait(ActivityStackSupervisor.java:2157) 
at com.android.server.am.ActivityManagerService.startActivityAsUser(ActivityManagerService.java:6336) 
at com.android.server.am.ActivityManagerService.startActivity(ActivityManagerService.java:6114) 
at android.app.ActivityManagerNative.onTransact(ActivityManagerNative.java:170) 
at com.android.server.am.ActivityManagerService.onTransact(ActivityManagerService.java:3986) 
at android.os.Binder.execTransact(Binder.java:453) 
Caused by: java.lang.NoClassDefFoundError: Class not found using the boot class loader; no stack trace available
11-23 21:34:04.451 29760-29760/? D/InstallAppProgress: Installation error code: -7
Pleas I'm stuck any hlp would be appreaciated.
Edit:
I found out that error code -7 means INSTALL_FAILED_UPDATE_INCOMPATIBLE. That means that signatures aren't matching. If I manage to change my key signing credentials on play store by reporting a lost key store and signing app with new keystore will solve the problem on playstore for existing users?

The Flutter APK installed successfully by uploading it to Play Console internal test track and updating it from there. Previouly I was trying to update it via putting APK in internal storage.

Android Studio Failed to load AppCompat ActionBar with unknown error

When I run my project in Android Studio, I get the follwoing error for XML documents, i.e. activity_main.xml. I am running Android Studio on an up to date install of Manjaro Linux with the latest LTS kernel.
Render Problem
Failed to load AppCompat ActionBar with unknown error.
Failed to instantiate one or more classes
The following classes could not be instantiated:
android.support.v7.widget.AppCompatImageView (Open Class, Show Exception, Clear Cache)
- android.support.v7.widget.Toolbar (Open Class, Show Exception, Clear Cache)
- android.support.v7.widget.AppCompatTextView (Open Class, Show Exception, Clear Cache)
- android.support.v7.widget.ActionBarContextView (Open Class, Show Exception, Clear Cache)
- android.support.v7.app.WindowDecorActionBar (Open Class, Show Exception, Clear Cache)
- android.support.v7.widget.ActionBarOverlayLayout (Open Class, Show Exception, Clear Cache)
Stack Trace:
java.lang.ClassNotFoundException: android.support.v4.view.TintableBackgroundView
at org.jetbrains.android.uipreview.ModuleClassLoader.load(ModuleClassLoader.java:181)
at com.android.tools.idea.rendering.RenderClassLoader.findClass(RenderClassLoader.java:56)
at org.jetbrains.android.uipreview.ModuleClassLoader.findClass(ModuleClassLoader.java:119)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at org.jetbrains.android.uipreview.ModuleClassLoader.loadClass(ModuleClassLoader.java:214)
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:763)
at java.lang.ClassLoader.defineClass(ClassLoader.java:642)
at com.android.tools.idea.rendering.RenderClassLoader.defineClassAndPackage(RenderClassLoader.java:177)
at com.android.tools.idea.rendering.RenderClassLoader.loadClassFromJar(RenderClassLoader.java:92)
at org.jetbrains.android.uipreview.ModuleClassLoader.load(ModuleClassLoader.java:171)
at com.android.tools.idea.rendering.RenderClassLoader.findClass(RenderClassLoader.java:56)
at org.jetbrains.android.uipreview.ModuleClassLoader.findClass(ModuleClassLoader.java:119)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at org.jetbrains.android.uipreview.ModuleClassLoader.loadClass(ModuleClassLoader.java:214)
at org.jetbrains.android.uipreview.ViewLoader.loadClass(ViewLoader.java:500)
at org.jetbrains.android.uipreview.ViewLoader.loadClass(ViewLoader.java:254)
at org.jetbrains.android.uipreview.ViewLoader.loadClass(ViewLoader.java:215)
at com.android.tools.idea.rendering.LayoutlibCallbackImpl.loadClass(LayoutlibCallbackImpl.java:218)
at android.view.BridgeInflater.loadCustomView(BridgeInflater.java:336)
at android.view.BridgeInflater.onCreateView(BridgeInflater.java:155)
at android.view.LayoutInflater.onCreateView(LayoutInflater.java:720)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:788)
at android.view.BridgeInflater.createViewFromTag(BridgeInflater.java:225)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:730)
at android.view.LayoutInflater.rInflate_Original(LayoutInflater.java:863)
at android.view.LayoutInflater_Delegate.rInflate(LayoutInflater_Delegate.java:72)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:837)
at android.view.LayoutInflater.inflate(LayoutInflater.java:489)
at com.android.layoutlib.bridge.bars.CustomBar.<init>(CustomBar.java:90)
at com.android.layoutlib.bridge.bars.NavigationBar.<init>(NavigationBar.java:52)
at com.android.layoutlib.bridge.bars.NavigationBar.<init>(NavigationBar.java:46)
at com.android.layoutlib.bridge.impl.Layout.createNavBar(Layout.java:325)
at com.android.layoutlib.bridge.impl.Layout.<init>(Layout.java:151)
at com.android.layoutlib.bridge.impl.RenderSessionImpl.inflate(RenderSessionImpl.java:288)
at com.android.layoutlib.bridge.Bridge.createSession(Bridge.java:384)
at com.android.tools.idea.layoutlib.LayoutLibrary.createSession(LayoutLibrary.java:193)
at com.android.tools.idea.rendering.RenderTask.createRenderSession(RenderTask.java:547)
at com.android.tools.idea.rendering.RenderTask.lambda$inflate$3(RenderTask.java:681)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)

try going to the build.gradle(module:app) file in your project, over there, change the following things:
implementation 'com.android.support:appcompat-v7:28.0.0-alpha3'
implementation 'com.android.support:design:28.0.0-alpha3'
to:
implementation 'com.android.support:appcompat-v7:28.0.0-alpha1'
implementation 'com.android.support:design:28.0.0-alpha1
'

Android parcelable class not fount exception in CI

I write a project in Android studio 2.3.3, I have JUnit test, also I use Jenkins as CI. My tasks in CI are clean,testDevDebugUnitTest. In past, my tests were working fine. Yesterday I removed folder build from my Android project and after that testDevDebugUnitTest always failed in CI.but In Android studio all is ok.
Stacktrace I am getting is as below:
java.lang.NoClassDefFoundError: android/os/Parcelable
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:763)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:467)
at java.net.URLClassLoader.access$100(URLClassLoader.java:73)
at java.net.URLClassLoader$1.run(URLClassLoader.java:368)
at java.net.URLClassLoader$1.run(URLClassLoader.java:362)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:361)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at ru.alfabank.oavdo.amc.base.models.Amount$Parser.parse(Amount.kt:135)
at ru.alfabank.oavdo.amc.base.models.Amount$Parser.parse(Amount.kt:114)
at ru.alfabank.oavdo.amc.base.models.AmountTest.parseTest(AmountTest.kt:78)
Caused by:
java.lang.ClassNotFoundException: android.os.Parcelable
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 15 more
I googled about this and found almost nothing, except that remove gradle folder, but after that project doesn't compile. Maybe anyone met this problem?

Make your model class implements with Serializable.

How to run the test project to test another application using JUnit?

I've got this peculiar issue while testing for an android project via a test project.
The test project runs on the emulator but does not run on the device. It shows the following error on the device:
"java.lang.NoClassDefFoundError: android/test/ActivityInstrumentationTestCase2
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:634)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:277)
at java.net.URLClassLoader.access$000(URLClassLoader.java:73)
at java.net.URLClassLoader$1.run(URLClassLoader.java:212)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:205)
at java.lang.ClassLoader.loadClass(ClassLoader.java:321)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:294)
at java.lang.ClassLoader.loadClass(ClassLoader.java:266)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.loadClass(RemoteTestRunner.java:693)
at o rg.eclipse.jdt.internal.junit.runner.RemoteTestRunner.loadClasses(RemoteTestRunner.java:429)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:452)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
Caused by: java.lang.ClassNotFoundException: android.test.ActivityInstrumentationTestCase2
at java.net.URLClassLoader$1.run(URLClassLoader.java:217)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:205)
at java.lang.ClassLoader.loadClass(ClassLoader.java:321)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:294)
at java.lang.ClassLoader.loadClass(ClassLoader.java:266)
... 17 more"
Why do I get java.lang.NoClassDefFoundError: android/test/ActivityInstrumentationTestCase2?