test_model_retry_specific_exceptions() — langchain Function Reference

Source Code

libs/langchain_v1/tests/unit_tests/agents/middleware/implementations/test_model_retry.py lines 290–319

def test_model_retry_specific_exceptions() -> None:
    """Test ModelRetryMiddleware only retries specific exception types."""
    # This model will fail with RuntimeError, which we won't retry
    model = AlwaysFailingModel(error_message="Runtime error", error_type=RuntimeError)

    # Only retry ValueError
    retry = ModelRetryMiddleware(
        max_retries=2,
        retry_on=(ValueError,),
        initial_delay=0.01,
        jitter=False,
        on_failure="continue",
    )

    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
    # RuntimeError should fail immediately (1 attempt only)
    assert "1 attempt" in ai_messages[-1].content