test_summarization_middleware_summary_creation() — langchain Function Reference

Source Code

libs/langchain_v1/tests/unit_tests/agents/middleware/implementations/test_summarization.py lines 171–220

def test_summarization_middleware_summary_creation() -> None:
    """Test SummarizationMiddleware summary creation."""
    middleware = SummarizationMiddleware(model=MockChatModel(), trigger=("tokens", 1000))

    # Test normal summary creation
    messages: list[AnyMessage] = [HumanMessage(content="Hello"), AIMessage(content="Hi")]
    summary = middleware._create_summary(messages)
    assert summary == "Generated summary"

    # Test empty messages
    summary = middleware._create_summary([])
    assert summary == "No previous conversation history."

    # Test error handling
    class ErrorModel(BaseChatModel):
        @override
        def invoke(
            self,
            input: LanguageModelInput,
            config: RunnableConfig | None = None,
            *,
            stop: list[str] | None = None,
            **kwargs: Any,
        ) -> AIMessage:
            msg = "Model error"
            raise ValueError(msg)

        @override
        def _generate(
            self,
            messages: list[BaseMessage],
            stop: list[str] | None = None,
            run_manager: CallbackManagerForLLMRun | None = None,
            **kwargs: Any,
        ) -> ChatResult:
            return ChatResult(generations=[ChatGeneration(message=AIMessage(content="Summary"))])

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

    middleware_error = SummarizationMiddleware(model=ErrorModel(), trigger=("tokens", 1000))
    summary = middleware_error._create_summary(messages)
    assert "Error generating summary: Model error" in summary

    # Test we raise warning if max_tokens_before_summary or messages_to_keep is specified
    with pytest.warns(DeprecationWarning, match="max_tokens_before_summary is deprecated"):
        SummarizationMiddleware(model=MockChatModel(), max_tokens_before_summary=500)
    with pytest.warns(DeprecationWarning, match="messages_to_keep is deprecated"):
        SummarizationMiddleware(model=MockChatModel(), messages_to_keep=5)