Using Mockito on Android

There are a few obstacles when trying to use Mockito on Android. However, they can be overcome easily: 0) Adding Mockito dependency to project:

androidTestCompile 'org.mockito:mockito-core:2.+'

1) Yields VerifyError exception:

java.lang.VerifyError: org/mockito/cglib/core/ReflectUtils
at org.mockito.cglib.core.KeyFactory$Generator.generateClass(KeyFactory.java:167)
at org.mockito.cglib.core.DefaultGeneratorStrategy.generate(DefaultGeneratorStrategy.java:25)
at org.mockito.cglib.core.AbstractClassGenerator.create(AbstractClassGenerator.java:217)
at org.mockito.cglib.core.KeyFactory$Generator.create(KeyFactory.java:145)
at org.mockito.cglib.core.KeyFactory.create(KeyFactory.java:117)
at org.mockito.cglib.core.KeyFactory.create(KeyFactory.java:109)
at org.mockito.cglib.core.KeyFactory.create(KeyFactory.java:105)
at org.mockito.cglib.proxy.Enhancer.(Enhancer.java:70)
at org.mockito.internal.creation.cglib.ClassImposterizer.createProxyClass(ClassImposterizer.java:99)
at org.mockito.internal.creation.cglib.ClassImposterizer.imposterise(ClassImposterizer.java:61)
at org.mockito.internal.creation.cglib.ClassImposterizer.imposterise(ClassImposterizer.java:53)
at org.mockito.internal.creation.cglib.CglibMockMaker.createMock(CglibMockMaker.java:24)
at org.mockito.internal.util.MockUtil.createMock(MockUtil.java:33)
at org.mockito.internal.MockitoCore.mock(MockitoCore.java:59)
at org.mockito.Mockito.mock(Mockito.java:1284)
at org.mockito.Mockito.mock(Mockito.java:1162)
at MyTest.java
at java.lang.reflect.Method.invokeNative(Native Method)
at android.test.InstrumentationTestCase.runMethod(InstrumentationTestCase.java:214)
at android.test.InstrumentationTestCase.runTest(InstrumentationTestCase.java:199)
at android.test.ActivityInstrumentationTestCase2.runTest(ActivityInstrumentationTestCase2.java:192)
at android.test.AndroidTestRunner.runTest(AndroidTestRunner.java:191)
at android.test.AndroidTestRunner.runTest(AndroidTestRunner.java:176)
at android.test.InstrumentationTestRunner.onStart(InstrumentationTestRunner.java:554)
at android.app.Instrumentation$InstrumentationThread.run(Instrumentation.java:1701)

Solution is adding the following dependency next to mockito:

    androidTestCompile 'com.google.dexmaker:dexmaker-mockito:1.2'

2) Yields another exception:

java.lang.IllegalArgumentException: dexcache == null (and no default could be found; consider setting the 'dexmaker.dexcache' system property)
at com.google.dexmaker.DexMaker.generateAndLoad(DexMaker.java:359)
at com.google.dexmaker.stock.ProxyBuilder.buildProxyClass(ProxyBuilder.java:258)
at com.google.dexmaker.mockito.DexmakerMockMaker.createMock(DexmakerMockMaker.java:55)
at org.mockito.internal.util.MockUtil.createMock(MockUtil.java:33)
at org.mockito.internal.MockitoCore.mock(MockitoCore.java:59)
at org.mockito.Mockito.mock(Mockito.java:1284)
at org.mockito.Mockito.mock(Mockito.java:1162)
at MyTest.java
at java.lang.reflect.Method.invokeNative(Native Method)
at android.test.InstrumentationTestCase.runMethod(InstrumentationTestCase.java:214)
at android.test.InstrumentationTestCase.runTest(InstrumentationTestCase.java:199)
at android.test.ActivityInstrumentationTestCase2.runTest(ActivityInstrumentationTestCase2.java:192)
at android.test.AndroidTestRunner.runTest(AndroidTestRunner.java:191)
at android.test.AndroidTestRunner.runTest(AndroidTestRunner.java:176)
at android.test.InstrumentationTestRunner.onStart(InstrumentationTestRunner.java:554)
at android.app.Instrumentation$InstrumentationThread.run(Instrumentation.java:1701)

See here: http://code.google.com/p/dexmaker/issues/detail?id=2

Add this to your setUp() or beforeClass() methods in the test class:

    System.setProperty("dexmaker.dexcache", getInstrumentation().getTargetContext().getCacheDir().getPath());