Mockito cannot mock class: Byte Buddy could not instrument all classes within the mock's type hierarchy

[Dominik Barwacz]

I can't mock external dependency mocked in tests. I don't think this specific issue has been raised before. 

Test is run with `RobolectricTestRunner.class` but not using it does not change the result. 

Full error stack: 

org.mockito.exceptions.base.MockitoException: 

Mockito cannot mock this class: class io.intercom.android.sdk.push.IntercomPushClient.

If you're not sure why you're getting this error, please report to the mailing list.

Java               : 1.8

JVM vendor name    : JetBrains s.r.o

JVM vendor version : 25.112-b736

JVM name           : OpenJDK 64-Bit Server VM

JVM version        : 1.8.0_112-release-b736

JVM info           : mixed mode

OS name            : Mac OS X

OS version         : 10.12.5

You are seeing this disclaimer because Mockito is configured to create inlined mocks.

You can learn about inline mocks and their limitations under item #39 of the Mockito class javadoc.

Underlying exception : org.mockito.exceptions.base.MockitoException: Could not modify all classes [class io.intercom.android.sdk.push.IntercomPushClient]

at ************************.setUp(**********.java:49)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

at java.lang.reflect.Method.invoke(Method.java:498)

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.RunBefores.evaluate(RunBefores.java:24)

at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:27)

at org.robolectric.internal.SandboxTestRunner$2.evaluate(SandboxTestRunner.java:209)

at org.robolectric.internal.SandboxTestRunner.runChild(SandboxTestRunner.java:109)

at org.robolectric.internal.SandboxTestRunner.runChild(SandboxTestRunner.java:36)

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.robolectric.internal.SandboxTestRunner$1.evaluate(SandboxTestRunner.java:63)

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 com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)

at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:51)

at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)

at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)

Caused by: org.mockito.exceptions.base.MockitoException: Could not modify all classes [class io.intercom.android.sdk.push.IntercomPushClient]

at net.bytebuddy.TypeCache.findOrInsert(TypeCache.java:138)

at net.bytebuddy.TypeCache$WithInlineExpunction.findOrInsert(TypeCache.java:346)

at net.bytebuddy.TypeCache.findOrInsert(TypeCache.java:161)

at net.bytebuddy.TypeCache$WithInlineExpunction.findOrInsert(TypeCache.java:355)

... 33 more

Caused by: java.lang.IllegalStateException: 

Byte Buddy could not instrument all classes within the mock's type hierarchy

This problem should never occur for javac-compiled classes. This problem has been observed for classes that are:

 - Compiled by older versions of scalac

 - Classes that are part of the Android distribution

at org.mockito.internal.creation.bytebuddy.InlineBytecodeGenerator.triggerRetransformation(InlineBytecodeGenerator.java:120)

at org.mockito.internal.creation.bytebuddy.InlineBytecodeGenerator.mockClass(InlineBytecodeGenerator.java:97)

at org.mockito.internal.creation.bytebuddy.TypeCachingBytecodeGenerator$1.call(TypeCachingBytecodeGenerator.java:37)

at org.mockito.internal.creation.bytebuddy.TypeCachingBytecodeGenerator$1.call(TypeCachingBytecodeGenerator.java:34)

at net.bytebuddy.TypeCache.findOrInsert(TypeCache.java:138)

at net.bytebuddy.TypeCache$WithInlineExpunction.findOrInsert(TypeCache.java:346)

at net.bytebuddy.TypeCache.findOrInsert(TypeCache.java:161)

at net.bytebuddy.TypeCache$WithInlineExpunction.findOrInsert(TypeCache.java:355)

at org.mockito.internal.creation.bytebuddy.TypeCachingBytecodeGenerator.mockClass(TypeCachingBytecodeGenerator.java:32)

at org.mockito.internal.creation.bytebuddy.InlineByteBuddyMockMaker.createMockType(InlineByteBuddyMockMaker.java:201)

at org.mockito.internal.creation.bytebuddy.InlineByteBuddyMockMaker.createMock(InlineByteBuddyMockMaker.java:182)

at org.mockito.internal.util.MockUtil.createMock(MockUtil.java:35)

at org.mockito.internal.MockitoCore.mock(MockitoCore.java:63)

at org.mockito.Mockito.mock(Mockito.java:1729)

at org.mockito.internal.configuration.MockAnnotationProcessor.process(MockAnnotationProcessor.java:33)

at org.mockito.internal.configuration.MockAnnotationProcessor.process(MockAnnotationProcessor.java:16)

at org.mockito.internal.configuration.IndependentAnnotationEngine.createMockFor(IndependentAnnotationEngine.java:38)

at org.mockito.internal.configuration.IndependentAnnotationEngine.process(IndependentAnnotationEngine.java:62)

at org.mockito.internal.configuration.InjectingAnnotationEngine.processIndependentAnnotations(InjectingAnnotationEngine.java:57)

at org.mockito.internal.configuration.InjectingAnnotationEngine.process(InjectingAnnotationEngine.java:41)

at org.mockito.MockitoAnnotations.initMocks(MockitoAnnotations.java:69)

... 33 more

Caused by: java.lang.NoClassDefFoundError: Lio/intercom/android/sdk/twig/Twig;

at java.lang.Class.getDeclaredFields0(Native Method)

at java.lang.Class.privateGetDeclaredFields(Class.java:2583)

at java.lang.Class.getDeclaredFields(Class.java:1916)

at net.bytebuddy.description.type.TypeDescription$ForLoadedType.getDeclaredFields(TypeDescription.java:7227)

at net.bytebuddy.dynamic.scaffold.InstrumentedType$Factory$Default$1.represent(InstrumentedType.java:222)

at net.bytebuddy.ByteBuddy.redefine(ByteBuddy.java:698)

at net.bytebuddy.ByteBuddy.redefine(ByteBuddy.java:676)

at org.mockito.internal.creation.bytebuddy.InlineBytecodeGenerator.transform(InlineBytecodeGenerator.java:167)

at sun.instrument.TransformerManager.transform(TransformerManager.java:188)

at sun.instrument.InstrumentationImpl.transform(InstrumentationImpl.java:428)

at sun.instrument.InstrumentationImpl.retransformClasses0(Native Method)

at sun.instrument.InstrumentationImpl.retransformClasses(InstrumentationImpl.java:144)

at org.mockito.internal.creation.bytebuddy.InlineBytecodeGenerator.triggerRetransformation(InlineBytecodeGenerator.java:117)

... 53 more

Caused by: java.lang.ClassNotFoundException: io.intercom.android.sdk.twig.Twig

at org.robolectric.internal.bytecode.SandboxClassLoader.getByteCode(SandboxClassLoader.java:161)

at org.robolectric.internal.bytecode.SandboxClassLoader.maybeInstrumentClass(SandboxClassLoader.java:108)

at org.robolectric.internal.bytecode.SandboxClassLoader.findClass(SandboxClassLoader.java:101)

at java.lang.ClassLoader.loadClass(ClassLoader.java:424)

at java.lang.ClassLoader.loadClass(ClassLoader.java:357)

... 66 more

What is interesting, `io.intercom.android.sdk.twig.Twig` is not found anywhere inside project. Can it be a problem with how library is built?