def test_strip(self): """test Tag.__strip__()""" node1 = Tag(wraptext("i"), wraptext("foobar")) node2 = Tag(wraptext("math"), wraptext("foobar")) node3 = Tag(wraptext("br"), self_closing=True) self.assertEqual("foobar", node1.__strip__()) self.assertEqual(None, node2.__strip__()) self.assertEqual(None, node3.__strip__())