JUnit-从类型转换返回模拟对象

Question

My code looks something like this:

ClassB objB = (ClassB) objA;
int z = objB.ClassBMethod();

int y = objA.ClassAMethod();

Currently my unit test looks like this:

ClassA mockClassA = mock(ClassA.class);
when(mockClassA.ClassAMethod()).thenReturn(1);

How would I mock objA 's cast to ClassB so that I can mock the ClassBMethod() ?

Answer 1

I really hope ClassB is a subclass of ClassA ... Try this:

ClassA mockB = mock(ClassB.class);

This will give you a mocked object that is really an instance of ClassB , but you treat it as a ClassA and then can successfully do the cast.