test_labeled_pairwise_string_comparison_chain_missing_ref() — langchain Function Reference

Source Code

libs/langchain/tests/unit_tests/evaluation/comparison/test_eval_chain.py lines 105–122

def test_labeled_pairwise_string_comparison_chain_missing_ref() -> None:
    llm = FakeLLM(
        queries={
            "a": "The values are the same.\n[[C]]",
            "b": "A is clearly better than b.\n[[A]]",
            "c": "B is clearly better than a.\n[[B]]",
        },
        sequential_responses=True,
    )
    chain = LabeledPairwiseStringEvalChain.from_llm(llm=llm)
    with pytest.raises(
        ValueError, match="LabeledPairwiseStringEvalChain requires a reference string"
    ):
        chain.evaluate_string_pairs(
            prediction="I like pie.",
            prediction_b="I love pie.",
            input="What is your favorite food?",
        )