def test_is_none_1(self): self.assertIsNone(vowel_shift(None, 0))
def test_equal_1(self): self.assertEqual(vowel_shift('', 0), '')
def test_equal_9(self): self.assertEqual(vowel_shift('AEIOUaeiou', 1), 'uAEIOUaeio')
def test_equal_8(self): self.assertEqual(vowel_shift('Brrrr', 99), 'Brrrr')
def test_equal_7(self): self.assertEqual(vowel_shift('This is a test!', -5), 'This as e tist!')
def test_equal_5(self): self.assertEqual(vowel_shift('This is a test!', 4), 'This is a test!')
def test_equal_3(self): self.assertEqual(vowel_shift('This is a test!', 1), 'Thes is i tast!')