def test_scrypt(self):
        backend = MultiBackend([DummyScryptBackend()])
        backend.derive_scrypt(b"key", b"salt", 1, 1, 1, 1)

        backend = MultiBackend([DummyBackend])
        with pytest.raises(UnsupportedAlgorithm):
            backend.derive_scrypt(b"key", b"salt", 1, 1, 1, 1)