When running the tests as part of the build, we want to run them in a consistent order and not automatically re-launch them in verbose mode when a failure occurs. -r Randomize test order -w Re-run failed tests in verbose mode diff -wpruN --no-dereference '--exclude=*.orig' a~/Lib/test/test_regrtest.py a/Lib/test/test_regrtest.py --- a~/Lib/test/test_regrtest.py 1970-01-01 00:00:00 +++ a/Lib/test/test_regrtest.py 1970-01-01 00:00:00 @@ -818,7 +818,7 @@ class ProgramsTestCase(BaseTestCase): self.tests = [self.create_test() for index in range(self.NTEST)] self.python_args = ['-Wd', '-E', '-bb'] - self.regrtest_args = ['-uall', '-rwW', + self.regrtest_args = ['-uall', '-W', '--testdir=%s' % self.tmptestdir] self.regrtest_args.extend(('--timeout', '3600', '-j4')) if sys.platform == 'win32':