def tearDown(self):
        super(SimpleInstanceTest, self).tearDown()
        CONF.network_label_regex = self.orig_conf
        CONF.ip_start = None
def test_critical_angle():
    m1 = Medium('m1', n=1)
    m2 = Medium('m2', n=1.33)
    assert ae(critical_angle(m2, m1), 0.85, 2)