@Test
    public void size() throws IllegalAccessException {
        Question q = mock(Question.class);

        assertFalse(blocker.isDuplicate(q));
        assertTrue(blocker.isDuplicate(q));
        for (int i = 0; i < limit; i++) {
            assertFalse(blocker.isDuplicate(mock(Question.class)));
        }
        assertFalse(blocker.isDuplicate(q));
        assertTrue(blocker.isDuplicate(q));
    }