examples/pytest/test_long_strings.py
import string

def get_string(s):
    return string.printable + s + string.printable

def test_long_strings():
    assert get_string('a') == get_string('b')

$ pytest test_long_strings.py

    def test_long_strings():
>       assert get_string('a') == get_string('b')
E       AssertionError: assert '0123456789ab...t\n\r\x0b\x0c' == '0123456789abc...t\n\r\x0b\x0c'
E         Skipping 90 identical leading characters in diff, use -v to show
E         Skipping 91 identical trailing characters in diff, use -v to show
E           {|}~
E
E         - a012345678
E         ? ^
E         + b012345678
E         ? ^