test_middleware_can_use_system_message_with_metadata() — langchain Function Reference

Source Code

libs/langchain_v1/tests/unit_tests/agents/test_system_message.py lines 797–817

    def test_middleware_can_use_system_message_with_metadata(self) -> None:
        """Test middleware creating SystemMessage with additional metadata."""

        def metadata_middleware(request: ModelRequest) -> SystemMessage:
            """Return SystemMessage with metadata."""
            return SystemMessage(
                content="You are a helpful assistant",
                additional_kwargs={"temperature": 0.7, "model": "gpt-4"},
                response_metadata={"region": "us-east"},
            )

        request = _make_request()
        new_system_message = metadata_middleware(request)

        assert len(new_system_message.content_blocks) == 1
        assert new_system_message.content_blocks[0].get("text") == "You are a helpful assistant"
        assert new_system_message.additional_kwargs == {
            "temperature": 0.7,
            "model": "gpt-4",
        }
        assert new_system_message.response_metadata == {"region": "us-east"}