def test_string_methods(self):
hiya = MutableString("Hiya")
self.assertEqual(hiya.replace('i', 'e'), "Heya")
self.assertEqual(hiya.upper(), "HIYA")
self.assertEqual(hiya.lower(), "hiya")
self.assertTrue(hiya.endswith('ya'))
self.assertFalse(hiya.endswith('ye'))
self.assertTrue(hiya.endswith(('a', 'e')))
self.assertFalse(hiya.endswith(('i', 'e')))
def test_correct_type_returned(self):
hiya = MutableString("hiya")
self.assertIs(type(hiya[-3]), MutableString)
self.assertIs(type(hiya[-3:]), MutableString)
self.assertEqual({type(c) for c in hiya}, {MutableString})
self.assertIs(type(hiya[0]), MutableString)
hiya[0] = "H"
self.assertIs(type(hiya[0]), MutableString)
self.assertIs(type(hiya + "!"), MutableString)
self.assertIs(type(hiya.replace('i', 'e')), MutableString)
self.assertIs(type(hiya.lower()), MutableString)