def test_true_2(self): self.assertTrue(is_opposite('aB', 'Ab'))
def test_true_1(self): self.assertTrue(is_opposite('ab', 'AB'))
def test_false_1(self): self.assertFalse(is_opposite('AB', 'Ab'))
def test_false_2(self): self.assertFalse(is_opposite('', ''))
def test_true_3(self): self.assertTrue(is_opposite('aBcd', 'AbCD'))