mockito #test #mock

mockito.java

when(someMock.someMethod()).thenAnswer(new Answer() {
    private int count = 0;

    public Object answer(InvocationOnMock invocation) {
        if (count++ == 1)
            return 1;

        return 2;
    }
});

# use captor to capture function arguments

ArgumentCaptor<HashSet> captor = ArgumentCaptor.forClass(HashSet.class);
verify(obj).update(anyString(), captor.capture());
assertEquals("the captured HashSet should be empty.", 0, captor.getValue().size());