def test_setdefault(self): pairs = [('c', 1), ('b', 2), ('a', 3), ('d', 4), ('e', 5), ('f', 6)] shuffle(pairs) od = OrderedDict(pairs) pair_order = list(od.items()) self.assertEqual(od.setdefault('a', 10), 3) # make sure order didn't change self.assertEqual(list(od.items()), pair_order) self.assertEqual(od.setdefault('x', 10), 10) # make sure 'x' is added to the end self.assertEqual(list(od.items())[-1], ('x', 10))