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.

Action bar rendering issue

I am new to Android Studio. I had this action bar disappearing in design panel. Basically nothing was being rendered on the design view. no action bar no textView nothing. then i read that i should switch my theme to some other theme and that worked but i wanted to keep the normal apptheme. API changing didnt do anything to it.
what worked was:
changing the appcompat line in build.gradle to
implementation 'com.android.support:appcompat-v7:26.0.0-beta1'
it started working like a charm until today.I was learning how fragments work so i made two blank fragments and the rendering issue came again. just to check it wasnt some bad luck:
I made a new project.
problem was there.
changed build.gradle file.
problem disappeared.
added 2 blank frags (with xml) to the proj.
problem came again.
now ill tell you what all ive done which doesnt work for me:
updated android studio
build.gradle appcompat code change
theme change (works but i want apptheme)
API change
changing style.xml(brings back textView in the design view but not the action bar)
please help.following is the stack :
java.lang.ClassNotFoundException: android.view.View$OnUnhandledKeyEventListener
at org.jetbrains.android.uipreview.ModuleClassLoader.load(ModuleClassLoader.java:180)
at com.android.tools.idea.rendering.RenderClassLoader.findClass(RenderClassLoader.java:61)
at org.jetbrains.android.uipreview.ModuleClassLoader.findClass(ModuleClassLoader.java:118)
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:213)
at android.support.v7.widget.ActionBarContainer.<init>(ActionBarContainer.java:64)
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.jetbrains.android.uipreview.ViewLoader.createNewInstance(ViewLoader.java:481)
at org.jetbrains.android.uipreview.ViewLoader.loadClass(ViewLoader.java:264)
at org.jetbrains.android.uipreview.ViewLoader.loadView(ViewLoader.java:222)
at com.android.tools.idea.rendering.LayoutlibCallbackImpl.loadView(LayoutlibCallbackImpl.java:209)
at android.view.BridgeInflater.loadCustomView(BridgeInflater.java:337)
at android.view.BridgeInflater.loadCustomView(BridgeInflater.java:348)
at android.view.BridgeInflater.createViewFromTag(BridgeInflater.java:248)
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.rInflateChildren(LayoutInflater.java:824)
at android.view.LayoutInflater.inflate(LayoutInflater.java:515)
at android.view.LayoutInflater.inflate(LayoutInflater.java:423)
at com.android.layoutlib.bridge.bars.BridgeActionBar.<init>(BridgeActionBar.java:89)
at com.android.layoutlib.bridge.bars.AppCompatActionBar.<init>(AppCompatActionBar.java:68)
at com.android.layoutlib.bridge.impl.Layout.createActionBar(Layout.java:277)
at com.android.layoutlib.bridge.impl.Layout.<init>(Layout.java:161)
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:544)
at com.android.tools.idea.rendering.RenderTask.lambda$inflate$3(RenderTask.java:678)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)

Try to use more stable version of the support library see if the issue goes away?
revisions for version 26 as stated Here are: 26.1.0, 26.0.2, 26.0.1

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.

Android Studio Rendering Error xml files

I am getting rendering error with android...Toolbarand android...ConstraintLayout in my xml files. However, in another application I am using exactly the same xml files and no problem occurs.
I am parallelly developing these two applications so not much things differ with each other yet I cannot understand it is doing this. I am using Android Studio 2.3.3.
Error:
Rendering failed with a known bug. Please try a rebuild.
The following classes could not be instantiated:
- android.support.v7.widget.AppCompatImageView (Open Class, Show Exception, Clear Cache)
- android.support.design.widget.AppBarLayout (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)
Tip: Use View.isInEditMode() in your custom views to skip code or show sample data when shown in the IDE. If this is an unexpected error you can also try to build the project, then manually refresh the layout.
Exception Details
java.lang.NoSuchFieldError: ViewBackgroundHelper
at android.support.v7.widget.AppCompatBackgroundHelper.loadFromAttributes(AppCompatBackgroundHelper.java:46)
at android.support.v7.widget.AppCompatImageView.<init>(AppCompatImageView.java:73)
at android.support.v7.widget.AppCompatImageView.<init>(AppCompatImageView.java:66)
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.jetbrains.android.uipreview.ViewLoader.createNewInstance(ViewLoader.java:475)
at org.jetbrains.android.uipreview.ViewLoader.loadClass(ViewLoader.java:262)
at org.jetbrains.android.uipreview.ViewLoader.loadClass(ViewLoader.java:213)
at com.android.tools.idea.rendering.LayoutlibCallbackImpl.loadClass(LayoutlibCallbackImpl.java:193)
at android.view.BridgeInflater.loadCustomView(BridgeInflater.java:333)
at android.view.BridgeInflater.onCreateView(BridgeInflater.java:152)
at android.view.LayoutInflater.onCreateView(LayoutInflater.java:717)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:785)
at android.view.BridgeInflater.createViewFromTag(BridgeInflater.java:222)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:727)
at android.view.LayoutInflater.rInflate_Original(LayoutInflater.java:858)
at android.view.LayoutInflater_Delegate.rInflate(LayoutInflater_Delegate.java:70)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:834)
at android.view.LayoutInflater.inflate(LayoutInflater.java:492)
at com.android.layoutlib.bridge.bars.CustomBar.<init>(CustomBar.java:95)
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:284)
at com.android.layoutlib.bridge.impl.Layout.<init>(Layout.java:140)
at com.android.layoutlib.bridge.impl.RenderSessionImpl.inflate(RenderSessionImpl.java:301)
at com.android.layoutlib.bridge.Bridge.createSession(Bridge.java:429)
at com.android.ide.common.rendering.LayoutLibrary.createSession(LayoutLibrary.java:368)
at com.android.tools.idea.rendering.RenderTask$2.compute(RenderTask.java:567)
at com.android.tools.idea.rendering.RenderTask$2.compute(RenderTask.java:549)
at com.intellij.openapi.application.impl.ApplicationImpl.runReadAction(ApplicationImpl.java:863)
at com.android.tools.idea.rendering.RenderTask.createRenderSession(RenderTask.java:549)
at com.android.tools.idea.rendering.RenderTask.lambda$inflate$1(RenderTask.java:680)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)

Make sure that you are using the library of ConstraintLayout...check in app:gradle

Being not 100% sure that my solution is stable, I simply replaced
compile 'com.android.support:appcompat-v7:26.+' with compile 'com.android.support:appcompat-v7:26.0.0-alpha1' and
compile 'com.android.support:design:26.+' with compile 'com.android.support:design:26.0.0-alpha1', their specific versions in app-level build.gradle.

Mocking my sqlite database

I am junit testing portions of my android app. I'm new to Android and my team is new to unit testing. (Sigh!!!)
So I want to grab our custom database adapter, and replace the Sqlite Database with a mocked one created using jmockit.
When I try this, it all looks good, but when I run it, I get:
java.lang.NoClassDefFoundError: android/database/sqlite/SQLiteDatabase
at java.lang.Class.getDeclaredMethods0(Native Method)
at java.lang.Class.privateGetDeclaredMethods(Class.java:2436)
at java.lang.Class.getDeclaredMethods(Class.java:1793)
at org.junit.internal.MethodSorter.getDeclaredMethods(MethodSorter.java:54)
at org.junit.runners.model.TestClass.<init>(TestClass.java:45)
at org.junit.runners.ParentRunner.<init>(ParentRunner.java:75)
at org.junit.runners.BlockJUnit4ClassRunner.<init>(BlockJUnit4ClassRunner.java:57)
at org.junit.internal.builders.JUnit4Builder.runnerForClass(JUnit4Builder.java:10)
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:26)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.<init>(JUnit4TestReference.java:33)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestClassReference.<init>(JUnit4TestClassReference.java:25)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestLoader.createTest(JUnit4TestLoader.java:48)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestLoader.loadTests(JUnit4TestLoader.java:38)
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.database.sqlite.SQLiteDatabase
at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
... 20 more
I don't know where to go from here. I tried searching for mocking sqlite, but didn't get far.

I ended up using robolectric from http://robolectric.org/ to provide my database class and let me move forward on this.