@Override
    public Predicate negate() {
        return new EqualPredicate(attributeName, value);
    }
@Test
    public void negate_thenReturnEqualPredicate() {
        NotEqualPredicate notEqualPredicate = new NotEqualPredicate("foo", 1);
        EqualPredicate negate = (EqualPredicate) notEqualPredicate.negate();

        assertEquals("foo", negate.attributeName);
        assertEquals(1, negate.value);
    }