Using PowerMock with Mockito

Note: PowerMock 1.2.5 only works with Mockito 1.7. PowerMock 1.3 works with 1.8

Basically, PowerMock provides a class called "PowerMockito" for creating mock object/class and initiating verification, everything else you can still use Mockito to setup and verify expectation (e.g. when(), times(), anyInt()).

All usages require @RunWith(PowerMockRunner.class) and @PrepareForTest annotated at class level.

Mocking Static Method

How to mock and stub:

1. Add @PrepareForTest at class level.

   @PrepareForTest(Static.class); // Static.class contains static methods

2. Call PowerMockito.mockStatic() to mock a static class (use PoweMockito.mockStaticPartial(class, method) to mock a specific method):

        PowerMockito.mockStatic(Static.class);

3. Just use Mockito.when() to setup your expectation:

        Mockito.when(Static.firstStaticMethod(param)).thenReturn(value);

How to verify behavior

1. Call PowerMockito.verifyStatic() to start verifying behavior (Important: You need to call verifyStatic() per method verification):

        PowerMockito.verifyStatic(Static.class);

2. Use EasyMock-like semantic to verify behavior:

        Static.firstStaticMethod(param);

How to use argument matchers

Mockito matchers are may still applied to a PowerMock mock. For example, using custom argument matchers per mocked static method:

PowerMockito.verifyStatic(Static.class);
Static.thirdStaticMethod(Mockito.anyInt());

How to verify exact number of calls

You can still use Mockito.VerificationMode (e.g Mockito.times(x)) with PowerMockito.verifyStatic():

PowerMockito.verifyStatic(Static.class, Mockito.times(1));

How to stub void static method to throw exception

This is not yet supported in current release 1.2.5

A full example for mocking, stubbing & verifying static method

@RunWith(PowerMockRunner.class)
@PrepareForTest(Static.class)
public class YourTestCase {
    @Test
    public void testMethodThatCallsStaticMethod() {
        // mock all the static methods in a class called "Static"
        PowerMockito.mockStatic(Static.class);
        // use Mockito to set up your expectation
        Mockito.when(Static.firstStaticMethod(param)).thenReturn(value);
        Mockito.when(Static.secondStaticMethod()).thenReturn(123);

        // execute your test
        classCallStaticMethodObj.execute();

        // Different from Mockito, always use PowerMockito.verifyStatic() first
        PowerMockito.verifyStatic(Static.class, Mockito.times(2));
        // Use EasyMock-like verification semantic per static method invocation
        Static.firstStaticMethod(param);

        // Remember to call verifyStatic() again
        PowerMockito.verifyStatic(Static.class); // default is once
        Static.secondStaticMethod();

        // Again, remember to call verifyStatic()
        PowerMockito.verifyStatic(Static.class, Mockito.never());
        Static.thirdStaticMethod();
    }
}

Partial Mocking

You can use PowerMock to partially mock a method which must be non-final.

How to mock and stub

1. Use PowerMockito.mockPartial(): (You can also use Annotation @Mock("methodToMock") or PowerMockito.mock() for a method with specific parameters)

  PartialMockClass mockObj = PowerMockito.mockPartial(PartialMockClass.class, "methodToMock");

2. Just use Mockito.when() to setup expectation:

  Mockito.when(mockObj.methodToMock()).thenReturn(123);

How to verify behavior

Just use Mockito.vertify() for verification:

    Mockito.verify(mockObj, times(2)).methodToMock();

How to argument matchers

Mockito matchers are may still applied to a PowerMock mock:

    Mockito.verify(mockObj).methodToMockToo(Mockito.anyInt());  

How to stub void static method to throw exception

Just use Mockito semantic of setting up void method stub:

    Mockito.doThrow(new RuntimeException("TEST")).when(mockObj).methodToMock();

A full example of partial mocking

@RunWith(PowerMockRunner.class)
@PrepareForTest(PartialMockClass.class)
public class YourTestCase {
    @Test
    public void testPartialMock() {
        // create a partially mocked object for method "methodToMock"
        PartialMockClass mockObj = PowerMockito.mockPartial(PartialMockClass.class, "methodToMock");
        // use Mockito to set up your expectation
        Mockito.when(mockObj.methodToMock()).thenReturn(value);

        // execute your test
        classCallPartialMockObj.execute();

        // Use Mockito.verify() to verify result
        Mockito.verify(mockObj, times(2)).methodToMock();
    }
}