test_with_listeners() — langchain Function Reference

Architecture documentation for the test_with_listeners() function in test_runnable.py from the langchain codebase.

Function python LangChainCore Runnables calls 1

Entity Profile

LangChainCore→ Runnables→ test_with_listeners() — langchain Function Reference

Dependency Diagram

graph TD
  726d1e44_659b_e411_088b_3b34eb2faba1["test_with_listeners()"]
  26df6ad8_0189_51d0_c3c1_6c3248893ff5["test_runnable.py"]
  726d1e44_659b_e411_088b_3b34eb2faba1 -->|defined in| 26df6ad8_0189_51d0_c3c1_6c3248893ff5
  a3895c50_dab4_0c36_2d24_f63121e198a0["invoke()"]
  726d1e44_659b_e411_088b_3b34eb2faba1 -->|calls| a3895c50_dab4_0c36_2d24_f63121e198a0
  style 726d1e44_659b_e411_088b_3b34eb2faba1 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

libs/core/tests/unit_tests/runnables/test_runnable.py lines 1639–1669

def test_with_listeners(mocker: MockerFixture) -> None:
    prompt = (
        SystemMessagePromptTemplate.from_template("You are a nice assistant.")
        + "{question}"
    )
    chat = FakeListChatModel(responses=["foo"])

    chain = prompt | chat

    mock_start = mocker.Mock()
    mock_end = mocker.Mock()

    chain.with_listeners(on_start=mock_start, on_end=mock_end).invoke(
        {"question": "Who are you?"}
    )

    assert mock_start.call_count == 1
    assert mock_start.call_args[0][0].name == "RunnableSequence"
    assert mock_end.call_count == 1

    mock_start.reset_mock()
    mock_end.reset_mock()

    with trace_as_chain_group("hello") as manager:
        chain.with_listeners(on_start=mock_start, on_end=mock_end).invoke(
            {"question": "Who are you?"}, {"callbacks": manager}
        )

    assert mock_start.call_count == 1
    assert mock_start.call_args[0][0].name == "RunnableSequence"
    assert mock_end.call_count == 1