Calling unittest.assertDictEqual for medium-size dictionaries takes too long

Calling assertDictEqual(d1, d2) / takes forever, even for medium-size dictionaries. To reproduce:

from unittest import TestCase
from random import randint

    def test_assert_dict(self):
        r = 10000000
        num = 10000
        d1 = dict((randint(0, r), randint(0, r)) for _ in range(num))
        d2 = dict((randint(0, r), randint(0, r)) for _ in range(num))
        self.assertDictEqual(d1, d2)

Probably related to issue #63416.

Tested on Python 3.10, Windows 11

Linked PRs

• gh-126923

Start with the supplied Python reproduction and inspect unittest.assertDictEqual, then read issue #63416 and linked PR gh-126923 for existing context. Done means the medium-size dictionary comparison no longer takes an excessive amount of time, with the behavior checked against the reproduction.