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_bad_url_error_message():
    values = [
        'google.com',
        'domain.google.com',
        'kevin:pass@google.com/path?query',
        u'google.com/path?\u2713',
    ]

    for value in values:
        yield check_url_error_message, value