Receiver class org.robolectric.shadows.multidex.Shadows does not define or inherit an implementation of getShadows() of interface ShadowProvider

Question

I am trying to run Android unit tests with Robolectric so I can access contexts in a multi-dex application. This is my build.gradle:

        implementation 'androidx.test.ext:junit:1.1.5'
        testImplementation 'junit:junit:4.13.2'
        testImplementation 'org.mockito:mockito-core:3.2.0'
        testImplementation 'org.robolectric:robolectric:4.9'
        testImplementation "org.robolectric:shadows-multidex:3.0"
        testImplementation 'androidx.test:core:1.5.0' 

When I try to run the tests I get the following error message during initialization:

Receiver class org.robolectric.shadows.multidex.Shadows does not define or inherit an implementation of the resolved method 'abstract java.util.Collection getShadows()' of interface org.robolectric.internal.ShadowProvider.
java.lang.AbstractMethodError: Receiver class org.robolectric.shadows.multidex.Shadows does not define or inherit an implementation of the resolved method 'abstract java.util.Collection getShadows()' of interface org.robolectric.internal.ShadowProvider.
    at org.robolectric.internal.bytecode.ShadowMap.createFromShadowProviders(ShadowMap.java:42)
    at org.robolectric.internal.bytecode.ShadowProviders.<init>(ShadowProviders.java:28)
    at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:490)
    at org.robolectric.util.inject.Injector.inject(Injector.java:250)
    at org.robolectric.util.inject.Injector.lambda$memoized$1(Injector.java:232)
    at org.robolectric.util.inject.Injector$MemoizingProvider.get(Injector.java:498)
    at org.robolectric.util.inject.Injector.getInstanceInternal(Injector.java:224)
    at org.robolectric.util.inject.Injector.getInstance(Injector.java:208)
    at org.robolectric.util.inject.Injector.getInstance(Injector.java:202)
    at org.robolectric.internal.SandboxTestRunner.<init>(SandboxTestRunner.java:79)
    at org.robolectric.RobolectricTestRunner.<init>(RobolectricTestRunner.java:106)
    at org.robolectric.RobolectricTestRunner.<init>(RobolectricTestRunner.java:101)
    at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:490)
    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:70)
    at org.junit.internal.builders.AllDefaultPossibilitiesBuilder.runnerForClass(AllDefaultPossibilitiesBuilder.java:37)
    at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:70)
    at org.junit.internal.requests.ClassRequest.createRunner(ClassRequest.java:28)
    at org.junit.internal.requests.MemoizingRequest.getRunner(MemoizingRequest.java:19)
    at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecutor.runTestClass(JUnitTestClassExecutor.java:78)
    at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecutor.execute(JUnitTestClassExecutor.java:58)
    at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecutor.execute(JUnitTestClassExecutor.java:38)
    at org.gradle.api.internal.tasks.testing.junit.AbstractJUnitTestClassProcessor.processTestClass(AbstractJUnitTestClassProcessor.java:62)
    at org.gradle.api.internal.tasks.testing.SuiteTestClassProcessor.processTestClass(SuiteTestClassProcessor.java:51)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:566)
    at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:36)
    at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
    at org.gradle.internal.dispatch.ContextClassLoaderDispatch.dispatch(ContextClassLoaderDispatch.java:33)
    at org.gradle.internal.dispatch.ProxyDispatchAdapter$DispatchingInvocationHandler.invoke(ProxyDispatchAdapter.java:94)
    at com.sun.proxy.$Proxy2.processTestClass(Unknown Source)
    at org.gradle.api.internal.tasks.testing.worker.TestWorker$2.run(TestWorker.java:176)
    at org.gradle.api.internal.tasks.testing.worker.TestWorker.executeAndMaintainThreadName(TestWorker.java:129)
    at org.gradle.api.internal.tasks.testing.worker.TestWorker.execute(TestWorker.java:100)
    at org.gradle.api.internal.tasks.testing.worker.TestWorker.execute(TestWorker.java:60)
    at org.gradle.process.internal.worker.child.ActionExecutionWorker.execute(ActionExecutionWorker.java:56)
    at org.gradle.process.internal.worker.child.SystemApplicationClassLoaderWorker.call(SystemApplicationClassLoaderWorker.java:133)
    at org.gradle.process.internal.worker.child.SystemApplicationClassLoaderWorker.call(SystemApplicationClassLoaderWorker.java:71)
    at worker.org.gradle.process.internal.worker.GradleWorkerMain.run(GradleWorkerMain.java:69)
    at worker.org.gradle.process.internal.worker.GradleWorkerMain.main(GradleWorkerMain.java:74)

Can anyone help me with this? Do we even need Robolectric for this anymore or does androidx finally allow testing of contexts?

Answer 1

Why org.robolectric:shadows-multidex:jar:3.0 , if you are using org.robolectric:robolectric:jar:4.9?
You might consider instead org.robolectric:shadows-multidex:jar:4.9.

Such a difference in version could explain the java.lang.AbstractMethodError you are seeing.
That error is pointing to a mismatch between the implementation of a method in a class and the declaration of that method in an interface that the class is supposed to implement. Specifically, it is stating that the org.robolectric.shadows.multidex.Shadows class does not have a correct implementation for the getShadows() method declared in the org.robolectric.internal.ShadowProvider interface.

Using a compatible version should help resolve that error.

The corrected build.gradle file would then be:

dependencies {
    implementation 'androidx.test.ext:junit:1.1.5'
    testImplementation 'junit:junit:4.13.2'
    testImplementation 'org.mockito:mockito-core:3.2.0'
    testImplementation 'org.robolectric:robolectric:4.9'
    testImplementation 'org.robolectric:shadows-multidex:4.9'  // version aligns with Robolectric version
    testImplementation 'androidx.test:core:1.5.0'
}

---

If you see a java.lang.NoClassDefFoundError: androidx/multidex/MultiDexApplication error, it means the MultiDexApplication class could not be found during runtime.
You may need to add the multidex library to your dependencies.

dependencies {
    implementation 'androidx.multidex:multidex:2.0.1'  // Add this line
    implementation 'androidx.test.ext:junit:1.1.5'
    testImplementation 'junit:junit:4.13.2'
    testImplementation 'org.mockito:mockito-core:3.2.0'
    testImplementation 'org.robolectric:robolectric:4.9'
    testImplementation 'org.robolectric:shadows-multidex:4.9'
    testImplementation 'androidx.test:core:1.5.0'
}