def test_dict_properties(): dic = {"length": sympify(1), "time": sympify(2)} d = Dimension(dic) assert d["length"] == 1 assert set(d.items()) == set(dic.items()) assert len(d) == 2 assert d.get("length") == 1 assert d.get("mass") is None assert ("length" in d) is True assert ("mass" in d) is False