Unable to mock static methods in instrumentation tests

Question

I am having a hard time in mocking static methods for instrumentation (Espresso) tests. For mocking objects, I am using Mockito. But, since Mockito cannot mock static methods , I am using Powermock on top of it. This works fine for tests running on the JVM machine, but for UI Tests, this combination does not work fine. I have declared the following dependencies for instrumentation tests.

androidTestCompile 'org.mockito:mockito-core:1.10.19'
androidTestCompile 'org.powermock:powermock-api-mockito:1.6.5'
androidTestCompile 'org.powermock:powermock-module-junit4:1.6.5' 
androidTestCompile 'com.google.dexmaker:dexmaker:1.2'
androidTestCompile 'com.google.dexmaker:dexmaker-mockito:1.2'
androidTestCompile 'com.android.support.test:runner:0.5'
androidTestCompile 'com.android.support.test.espresso:espresso-core:2.2.2'

I am writing a sample test as below.

@RunWith(PowerMockRunner.class)
@PowerMockRunnerDelegate(AndroidJUnit4.class)

public class SampleTest {

  @Test
  public void test(){
    //Test Code.
  }
}

The code compiles successfully, but on run time, it gives me the following exception

java.lang.IllegalStateException: Extension API internal error: org.powermock.api.extension.proxyframework.ProxyFrameworkImpl could not be located in classpath.
at org.powermock.reflect.proxyframework.ProxyFrameworkHelper.register(ProxyFrameworkHelper.java:35)
at org.powermock.reflect.proxyframework.ClassLoaderRegisterProxyFramework.registerProxyframework(ClassLoaderRegisterProxyFramework.java:28)
at org.powermock.tests.utils.impl.AbstractCommonTestSuiteChunkerImpl.registerProxyframework(AbstractCommonTestSuiteChunkerImpl.java:101)
at org.powermock.tests.utils.impl.AbstractCommonTestSuiteChunkerImpl.chunkClass(AbstractCommonTestSuiteChunkerImpl.java:114)
at org.powermock.tests.utils.impl.AbstractCommonTestSuiteChunkerImpl.<init>(AbstractCommonTestSuiteChunkerImpl.java:60)
at org.powermock.tests.utils.impl.AbstractCommonTestSuiteChunkerImpl.<init>(AbstractCommonTestSuiteChunkerImpl.java:54)
at org.powermock.tests.utils.impl.AbstractTestSuiteChunkerImpl.<init>(AbstractTestSuiteChunkerImpl.java:58)
at org.powermock.modules.junit4.common.internal.impl.JUnit4TestSuiteChunkerImpl.<init>(JUnit4TestSuiteChunkerImpl.java:59)
at org.powermock.modules.junit4.common.internal.impl.AbstractCommonPowerMockRunner.<init>(AbstractCommonPowerMockRunner.java:32)
at org.powermock.modules.junit4.PowerMockRunner.<init>(PowerMockRunner.java:34)
at java.lang.reflect.Constructor.newInstance(Native Method)
at org.junit.internal.builders.AnnotatedBuilder.buildRunner(AnnotatedBuilder.java:104)
at org.junit.internal.builders.AnnotatedBuilder.runnerForClass(AnnotatedBuilder.java:86)
at android.support.test.internal.runner.junit4.AndroidAnnotatedBuilder.runnerForClass(AndroidAnnotatedBuilder.java:77)
at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:59)
at org.junit.internal.builders.AllDefaultPossibilitiesBuilder.runnerForClass(AllDefaultPossibilitiesBuilder.java:26)
at org.junit.runner.Computer.getRunner(Computer.java:40)
at org.junit.runner.Computer$1.runnerForClass(Computer.java:31)
at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:59)
at org.junit.runners.model.RunnerBuilder.runners(RunnerBuilder.java:101)
at org.junit.runners.model.RunnerBuilder.runners(RunnerBuilder.java:87)
at org.junit.runners.Suite.<init>(Suite.java:81)
at org.junit.runner.Computer.getSuite(Computer.java:28)
at android.support.test.internal.runner.TestRequestBuilder.classes(TestRequestBuilder.java:789)
at android.support.test.internal.runner.TestRequestBuilder.build(TestRequestBuilder.java:753)
at android.support.test.runner.AndroidJUnitRunner.buildRequest(AndroidJUnitRunner.java:354)
at android.support.test.runner.AndroidJUnitRunner.onStart(AndroidJUnitRunner.java:260)
at android.app.Instrumentation$InstrumentationThread.run(Instrumentation.java:1879)

What else am I missing? Is there any way in which static methods can be mocked in Espresso tests?

Answer 1

You can use Powermock to mock static methods. I used it to mock Log.java class in my application. Have a look on the example below :

@RunWith(PowerMockRunner.class)
@PrepareForTest({Log.class})

public class PowermockStaticExample {

//fixme : complete with your members

@Before
public void setUp() throws Exception {
  PowerMockito.mockStatic(YourStaticClass.class);
  //Use Powermock annotation to mock what you want to
}

//fixme : complete with your methods to test

Answer 2

PowerMock doesn't work with Espresso see this issue