import sys def expect_cannot_fit_index_error(s, index): try: s[index] except IndexError as error: assert str(error) == "cannot fit 'int' into an index-sized integer" else: assert False MAX_INDEX = sys.maxsize + 1 MIN_INDEX = -(MAX_INDEX + 1) test_str = "test" expect_cannot_fit_index_error(test_str, MIN_INDEX) expect_cannot_fit_index_error(test_str, MAX_INDEX) test_list = [0, 1, 2, 3] expect_cannot_fit_index_error(test_list, MIN_INDEX) expect_cannot_fit_index_error(test_list, MAX_INDEX)