def get_dir_from_zipfile(zip_file, fallback=None):
    """Return the name of the root folder in a zip file.

    :param zip_file: a :class:`zipfile.ZipFile` instance.
    :param fallback: if `None`, the name of the zip file is used. This is
        returned if the zip file contains more than one top-level directory,
        or none at all.
    """
    fallback = fallback or zip_file.filename
    directories = [name for name in zip_file.namelist() if name.endswith("/")
                   and len(PurePath(name).parts) == 1]
    return fallback if len(directories) > 1 else directories[0]
def test_rule_300(self):
        oRule = iteration_scheme.rule_300()
        self.assertTrue(oRule)
        self.assertEqual(oRule.name, 'iteration_scheme')
        self.assertEqual(oRule.identifier, '300')

        lExpected = [13, 17]

        oRule.analyze(self.oFile)
        self.assertEqual(lExpected, utils.extract_violation_lines_from_violation_object(oRule.violations))