def METHOD_NAME(self):
    """Check that the owner function works."""
    path = Path(tempfile.mktemp())
    with path.open('w') as file:
        file.write('hi there')
    self.assertEqual(utils.owner(path), getpass.getuser())
    # Try to set the permissions of the file to an unknown user.
    proc = sp.Popen(['sudo', '-n', 'chown', '12341', path.as_posix()],
                    stdout=sp.PIPE, stderr=sp.PIPE, stdin=sp.PIPE)
    if proc.wait(1) == 0:
        self.assertEqual(utils.owner(path), "<unknown user '12341'>")