def __init__(self, package, version):
        """Construct a new requirement.

        :param package: the package name.
        :param version: a semver compatible version specification.
        """
        self.package = package
        self.version = version
        if self.version and not re.match(r"[<=>~]", version[:2]):
            self.version = "=={}".format(self.version)
def test_bad_isointervals():
    bad_intervals = [
        '2013-01T14:',
        '',
        'asdf',
        '01/01/2013',
    ]

    for bad_interval in bad_intervals:
        yield (
            assert_raises,
            Exception,
            inputs.iso8601interval,
            bad_interval,
        )