Mocking method for all instances of class with PowerMockito

Question

I am trying to mock a method whatever the instance that calls this method is. As far as I could got reading this can't happen with Mockito and should be done with PowerMockito, but I can't figure out the way it should be done. I have

public class B{
    public void veryAnnoyingMethod(int i, short s){}
}
public class A{
    public void veryImportantMethod(){
        B newB = new B();
        newB.veryAnnoyingMethod(i,s);
        ...
    }
}

I am trying to test the veryImportantMethod() and want to mock the veryAnnoyingMethod(). I don't want to mock the constructor as explained here: Mocking methods of local scope objects with Mockito because apart from the veryAnnoyingMethod() I need the newB fully functional.

I have come up with something like:

B dummyB = PowerMockito.spy(new B());
PowerMockito.doReturn(null).when(dummyB.veryAnnoyingMethod(Mockito.anyInt(), Mockito.anyShort()));

But it throws exception, and I don't think it is what I actually need.

UPDATE

After a bit more reading it seems I have to use PowerMockito.stub, or PowerMockito.supress. So I have tried the following:

PowerMockito.stub(PowerMockito.method(B.class, "veryAnnoyingMethod", int.class, short.class)).toReturn(null);

or

PowerMockito.supress(PowerMockito.method(B.class, "veryAnnoyingMethod", int.class, short.class));

But with either the method is still executed

score 4 · Accepted Answer · edited May 31 '18 at 04:53

OK, I finally got it to work. Using either of stub and suppress is working. The test looks something like this:

@RunWith(PowerMockRunner.class)
@PrepareForTest(B.class)
class TestClassAWithPowerMockito{
    @Test
    public void testVeryImportantMethod() throws Exception {
        A a = new A();
        PowerMockito.suppress(PowerMockito.method(B.class, "veryAnnoyingMethod", int.class, short.class));
        a.veryImportantMethod();
        ...
    }
}

Note the @RunWith(PowerMockRunner.class) and @PrepareForTest(B.class) I had to take the test using PowerMockito in separate class because adding these 2 notations made some of my other tests (which do not use PowerMockito, but only Mockito) fail.

Hope this is clear, and helps someone who is struggling with a similar problem.

Mocking method for all instances of class with PowerMockito

1 Answers1