test_middleware_error_behavior() — langchain Function Reference

Source Code

libs/langchain_v1/tests/unit_tests/agents/middleware/implementations/test_tool_call_limit.py lines 228–252

def test_middleware_error_behavior() -> None:
    """Test middleware error behavior.

    Test that middleware raises ToolCallLimitExceededError when configured with
    exit_behavior='error'.
    """
    middleware = ToolCallLimitMiddleware(thread_limit=2, exit_behavior="error")
    runtime = None

    state = ToolCallLimitState(
        messages=[AIMessage("Response", tool_calls=[{"name": "search", "args": {}, "id": "1"}])],
        thread_tool_call_count={"__all__": 2},
        run_tool_call_count={"__all__": 2},
    )

    with pytest.raises(ToolCallLimitExceededError) as exc_info:
        middleware.after_model(state, runtime)  # type: ignore[arg-type]

    error = exc_info.value
    # Thread count in error message shows hypothetical count (what it would have been)
    assert error.thread_count == 3
    assert error.thread_limit == 2
    # Run count includes the blocked call
    assert error.run_count == 3
    assert error.tool_name is None