test_run_limit_resets_between_invocations() — langchain Function Reference

Source Code

libs/langchain_v1/tests/unit_tests/agents/middleware/implementations/test_model_call_limit.py lines 204–227

def test_run_limit_resets_between_invocations() -> None:
    """Test run limit resets between invocations.

    Test that run_model_call_count resets between invocations, but
    thread_model_call_count accumulates.
    """
    # First: No tool calls per invocation, so model does not increment call counts internally
    middleware = ModelCallLimitMiddleware(thread_limit=3, run_limit=1, exit_behavior="error")
    model = FakeToolCallingModel(
        tool_calls=[[], [], [], []]
    )  # No tool calls, so only model call per run

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

    thread_config = {"configurable": {"thread_id": "test_thread"}}
    agent.invoke({"messages": [HumanMessage("Hello")]}, thread_config)
    agent.invoke({"messages": [HumanMessage("Hello again")]}, thread_config)
    agent.invoke({"messages": [HumanMessage("Hello third")]}, thread_config)

    # Fourth run: should raise, thread_model_call_count == 3 (limit)
    with pytest.raises(ModelCallLimitExceededError) as exc_info:
        agent.invoke({"messages": [HumanMessage("Hello fourth")]}, thread_config)
    error_msg = str(exc_info.value)
    assert "thread limit (3/3)" in error_msg