def test_model_is_subclass_raises_error_on_invalid_model():
    class LOL(object):
        pass

    with pytest.raises(InvalidModel):
        tuple(walk_from_model_to_root(A, LOL))
    with pytest.raises(TypeError):
        tuple(walk_from_model_to_root(A, LOL))
def test_model_is_subclass_ok():
    tuple(walk_from_model_to_root(A, AB))