ClassCastException exception when running 2 Roboel

Question

I have 2 test-classes: MyTest1 and MyTest2. They both have the same header and test the same class but they test 2 very different aspects of that class (you may criticize me for that but let us not discuss that here):

@RunWith(LocalRobolectricTestRunner.class)
@Config(manifest = RobolectricTestData.AndroidManifestFileName)
@TargetApi(Build.VERSION_CODES.JELLY_BEAN)
@PowerMockIgnore({ "org.mockito.*", "org.robolectric.*", "android.*" })
@PrepareForTest(MyStrangeClassWithStaticMethods.class)
@ParametersAreNonnullByDefault
public class MyTest1 extends MyBaseTest {

    // This is to dinamically load PowerMock. We can't use PowerMockRunner because we already use
    // RobolectricTestRunner and PowerMockRunner doesn't do robolectric's stuff.
    @Rule
    public final PowerMockRule rule = new PowerMockRule();

    /**
     * Tests set up.
     */
    @Before
    public final void setUp() throws Exception {
        super.setUp();
    }
    public void testSomething() {
        PowerMockito.mockStatic(MyStrangeClassWithStaticMethods.class);
        // do some stuff
    }
}

The problem is that I can run separately MyTest1 and all tests go OK. I can run separately MyTest2 and all tests go OK. But when I run all tests of both MyTest1 and MyTest2 (they are compiled into one jar) - when I do this, only first run class (MyTest1) goes OK and the second class fails. All tests crash with this exception:

    org.mockito.exceptions.base.MockitoException: 
ClassCastException occurred while creating the mockito proxy :
  class to imposterize : 'com.my.project.MyStrangeClassWithStaticMethods', loaded by classloader : 'org.powermock.core.classloader.MockClassLoader@2617b42c'
  imposterizing class : 'com.my.project.MyStrangeClassWithStaticMethods$$EnhancerByMockitoWithCGLIB$$41f09512', loaded by classloader : 'org.mockito.internal.creation.jmock.SearchingClassLoader@230eec25'
  proxy instance class : 'com.my.project.MyStrangeClassWithStaticMethods$$EnhancerByMockitoWithCGLIB$$41f09512', loaded by classloader : 'org.mockito.internal.creation.jmock.SearchingClassLoader@23a0547b'

You might experience classloading issues, disabling the Objenesis cache *might* help (see MockitoConfiguration)
    at org.powermock.api.mockito.internal.mockcreation.MockCreator.createMethodInvocationControl(MockCreator.java:109)
    at org.powermock.api.mockito.internal.mockcreation.MockCreator.mock(MockCreator.java:57)
    at org.powermock.api.mockito.PowerMockito.mockStatic(PowerMockito.java:70)
    at com.my.project.MyTest2.testSomething(MyTest2.java:66666<no matter what line number>)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:45)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:42)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
    at org.powermock.modules.junit4.rule.PowerMockStatement$1.run(PowerMockRule.java:52)
    at sun.reflect.GeneratedMethodAccessor26.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.powermock.reflect.internal.WhiteboxImpl.performMethodInvocation(WhiteboxImpl.java:1873)
    at org.powermock.reflect.internal.WhiteboxImpl.doInvokeMethod(WhiteboxImpl.java:773)
    at org.powermock.reflect.internal.WhiteboxImpl.invokeMethod(WhiteboxImpl.java:638)
    at org.powermock.reflect.Whitebox.invokeMethod(Whitebox.java:401)
    at org.powermock.classloading.ClassloaderExecutor.execute(ClassloaderExecutor.java:98)
    at org.powermock.classloading.ClassloaderExecutor.execute(ClassloaderExecutor.java:78)
    at org.powermock.modules.junit4.rule.PowerMockStatement.evaluate(PowerMockRule.java:49)
    at org.robolectric.RobolectricTestRunner$2.evaluate(RobolectricTestRunner.java:251)
    at org.robolectric.RobolectricTestRunner.runChild(RobolectricTestRunner.java:188)
    at org.robolectric.RobolectricTestRunner.runChild(RobolectricTestRunner.java:54)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:231)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:60)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:229)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:50)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:222)
    at org.robolectric.RobolectricTestRunner$1.evaluate(RobolectricTestRunner.java:152)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:300)
    at org.chromium.testing.local.GtestComputer$GtestSuiteRunner.run(GtestComputer.java:46)
    at org.junit.runners.Suite.runChild(Suite.java:128)
    at org.junit.runners.Suite.runChild(Suite.java:24)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:231)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:60)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:229)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:50)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:222)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:300)
    at org.junit.runner.JUnitCore.run(JUnitCore.java:157)
    at org.junit.runner.JUnitCore.run(JUnitCore.java:136)
    at org.chromium.testing.local.JunitTestMain.main(JunitTestMain.java:105)
Caused by: java.lang.ClassCastException: Cannot cast com.my.project.MyStrangeClassWithStaticMethods$$EnhancerByMockitoWithCGLIB$$41f09512 to com.my.project.MyStrangeClassWithStaticMethods
    at java.lang.Class.cast(Class.java:3176)
    at org.mockito.internal.creation.jmock.ClassImposterizer.imposterise(ClassImposterizer.java:62)
    ... 47 more

This crash forces me to merge my 2 classes into 1 test class. And this probably blocks me a possibility to mock MyStrangeClassWithStaticMethods.class in another test class. I can mock it only once :(

The issue looks like ClassCastException exception when running Robolectric test with Power Mock on multiple files but a little different and needs another solution.

Powermock 1.6.0

Mockito 1.10.5

Robolectric 3.0

Answer 1

I found a solution. The stack trace says:

disabling the Objenesis cache might help (see MockitoConfiguration)

I did it and it worked. Just add this class to your tests source location:

package org.mockito.configuration;

public class MockitoConfiguration extends DefaultMockitoConfiguration {
    @Override
    public boolean enableClassCache() {
        return false;
    }
}