def coerce(cls, string):
        """Create a :class:`Requirement` object from a given package spec."""
        match = re.match(cls.spec_regex, string)
        if not match:
            raise InvalidRequirementSpecError("could not parse requirement")
        package = match.group(1)
        if all(match.group(2, 3)):
            version = "".join(match.group(2, 3))
        else:
            version = None
        return cls(package, version)
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))