def test_user_id_partition_keygen_raise_error_when_context_null(self):
        with self.assertRaises(PersistenceException) as exc:
            user_id_partition_keygen(request_envelope=self.request_envelope)

        assert "Couldn't retrieve user id from request envelope" in str(
            exc.exception), (
            "User Id Partition Key Generation didn't throw exception when "
            "null context provided in request envelope")
    def test_valid_user_id_partition_keygen(self):
        self.user.user_id = "123"
        self.system.user = self.user
        self.context.system = self.system
        self.request_envelope.context = self.context

        assert user_id_partition_keygen(self.request_envelope) == "123", (
            "User Id Partition Key Generation retrieved wrong user id from "
            "valid request envelope")