def test_duration_xmlduration(self):
        dur = XmlDuration(days=2, seconds=3)

        element = etree.Element('test')
        Duration.to_parent_element(dur, ns_test, element)
        element = element[0]

        self.assertEquals(element.text, 'P2DT3S')
        du = Duration.from_xml(element)
        self.assertEquals(dur.as_timedelta(), du)
    def test_duration_timedelta(self):
        delta = datetime.timedelta(days=2, seconds=3)

        element = etree.Element('test')
        Duration.to_parent_element(delta, ns_test, element)
        element = element[0]

        self.assertEquals(element.text, 'P2DT3S')
        du = Duration.from_xml(element)
        self.assertEquals(delta, du)