test_summarization_middleware_initialization() — langchain Function Reference

Source Code

libs/langchain_v1/tests/unit_tests/agents/middleware/implementations/test_summarization.py lines 84–113

def test_summarization_middleware_initialization() -> None:
    """Test SummarizationMiddleware initialization."""
    model = FakeToolCallingModel()
    middleware = SummarizationMiddleware(
        model=model,
        trigger=("tokens", 1000),
        keep=("messages", 10),
        summary_prompt="Custom prompt: {messages}",
    )

    assert middleware.model == model
    assert middleware.trigger == ("tokens", 1000)
    assert middleware.keep == ("messages", 10)
    assert middleware.summary_prompt == "Custom prompt: {messages}"
    assert middleware.trim_tokens_to_summarize == 4000

    with pytest.raises(
        ValueError,
        match="Model profile information is required to use fractional token limits, "
        "and is unavailable for the specified model",
    ):
        SummarizationMiddleware(model=model, keep=("fraction", 0.5))  # no model profile

    # Test with string model
    with patch(
        "langchain.agents.middleware.summarization.init_chat_model",
        return_value=FakeToolCallingModel(),
    ):
        middleware = SummarizationMiddleware(model="fake-model")
        assert isinstance(middleware.model, FakeToolCallingModel)