def test_reverse_iter(self):
     # this test if the function can reverse an empty string
     self.assertEqual(sample.reverse_iter(""),"")
     # this test if the function can reverse a simply string with letters
     self.assertEqual(sample.reverse_iter("abcd"),"dcba")
     # test the reverse function with a mixed of input
     self.assertEqual(sample.reverse_iter("123abcd"), "dcba321")
     self.assertEqual(sample.reverse_iter("123 _abcd"), "dcba_ 321")
     self.assertEqual(sample.reverse_iter("+ = -"), "- = +")
 def test_reverse_iter(self):
     self.assertEqual(sample.reverse_iter(""),"")
     self.assertEqual(sample.reverse_iter("abcd"),"dcba")