Method _check_random_seed

Lib/test/test_regrtest.py:2121–2153

(self, run_workers: bool)

                                  stats=TestStats(1, 1, 0))

    def _check_random_seed(self, run_workers: bool):
        # gh-109276: When -r/--randomize is used, random.seed() is called
        # with the same random seed before running each test file.
        code = textwrap.dedent(r'''
            import random
            import unittest

            class RandomSeedTest(unittest.TestCase):
                def test_randint(self):
                    numbers = [random.randint(0, 1000) for _ in range(10)]
                    print(f"Random numbers: {numbers}")
        ''')
        tests = [self.create_test(name=f'test_random{i}', code=code)
                 for i in range(1, 3+1)]

        random_seed = 856_656_202
        cmd = ["--randomize", f"--randseed={random_seed}"]
        if run_workers:
            # run as many worker processes than the number of tests
            cmd.append(f'-j{len(tests)}')
        cmd.extend(tests)
        output = self.run_tests(*cmd)

        random.seed(random_seed)
        # Make the assumption that nothing consume entropy between libregrest
        # setup_tests() which calls random.seed() and RandomSeedTest calling
        # random.randint().
        numbers = [random.randint(0, 1000) for _ in range(10)]
        expected = f"Random numbers: {numbers}"

        regex = r'^Random numbers: .*$'
        matches = re.findall(regex, output, flags=re.MULTILINE)
        self.assertEqual(matches, [expected] * len(tests))

    def test_random_seed(self):
        self._check_random_seed(run_workers=False)