test_model_retry_succeeds_after_retries() — langchain Function Reference

Source Code

libs/langchain_v1/tests/unit_tests/agents/middleware/implementations/test_model_retry.py lines 261–287

def test_model_retry_succeeds_after_retries() -> None:
    """Test ModelRetryMiddleware succeeds after temporary failures."""
    model = TemporaryFailureModel(fail_count=2)

    retry = ModelRetryMiddleware(
        max_retries=3,
        initial_delay=0.01,
        jitter=False,
    )

    agent = create_agent(
        model=model,
        tools=[],
        middleware=[retry],
        checkpointer=InMemorySaver(),
    )

    result = agent.invoke(
        {"messages": [HumanMessage("Hello")]},
        {"configurable": {"thread_id": "test"}},
    )

    ai_messages = [m for m in result["messages"] if isinstance(m, AIMessage)]
    assert len(ai_messages) >= 1
    # Should succeed on 3rd attempt
    assert "Success after 3 attempts" in ai_messages[-1].content
    assert model.attempt == 3