test_summarization_middleware_missing_profile() — langchain Function Reference

Source Code

libs/langchain_v1/tests/unit_tests/agents/middleware/implementations/test_summarization.py lines 390–421

def test_summarization_middleware_missing_profile() -> None:
    """Ensure automatic profile inference falls back when profiles are unavailable."""

    class ImportErrorProfileModel(BaseChatModel):
        @override
        def _generate(
            self,
            messages: list[BaseMessage],
            stop: list[str] | None = None,
            run_manager: CallbackManagerForLLMRun | None = None,
            **kwargs: Any,
        ) -> ChatResult:
            raise NotImplementedError

        @property
        def _llm_type(self) -> str:
            return "mock"

        # NOTE: Using __getattribute__ because @property cannot override Pydantic fields.
        def __getattribute__(self, name: str) -> Any:
            if name == "profile":
                msg = "Profile not available"
                raise AttributeError(msg)
            return super().__getattribute__(name)

    with pytest.raises(
        ValueError,
        match="Model profile information is required to use fractional token limits",
    ):
        _ = SummarizationMiddleware(
            model=ImportErrorProfileModel(), trigger=("fraction", 0.5), keep=("messages", 1)
        )