Tests fail in Python 3.10

[Cyril Roelandt]

$ tox -epy310

cliff.tests.test_help.TestHelp.test_show_help_for_help
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Captured traceback:
~~~~~~~~~~~~~~~~~~~
    Traceback (most recent call last):

      File "/home/vagrant/projects/cliff/cliff/tests/test_help.py", line 104, in test_show_help_for_help
    self.assertIn('optional arguments:\n --version', help_text)

      File "/home/vagrant/projects/cliff/.tox/py310/lib/python3.10/site-packages/testtools/testcase.py", line 399, in assertIn
    self.assertThat(haystack, Contains(needle), message)

      File "/home/vagrant/projects/cliff/.tox/py310/lib/python3.10/site-packages/testtools/testcase.py", line 480, in assertThat
    raise mismatch_error

    testtools.matchers._impl.MismatchError: 'optional arguments:\n --version' not in "usage: run.py [--version] [-v | -q] [--log-file LOG_FILE] [-h] [--debug]\n\ntesting\n\noptions:\n --version show program's version number and exit\n -v, --verbose Increase verbosity of output. Can be repeated.\n -q, --quiet Suppress output except warnings and errors.\n --log-file LOG_FILE Specify a file to log output. Disabled by default.\n -h, --help Show help message and exit.\n --debug Show tracebacks on errors.\n\nCommands:\n complete print bash completion command\n help print detailed help for another command\n one Test command.\n three word command Test command.\n two words Test command.\n"

[Cyril Roelandt (cyril-roelandt)]

Fixed with https://review.opendev.org/c/openstack/cliff/+/775091