yes the linked thread describes testing it via shaking it and hearing for a rattle and by looking inside the valve at how clean it is. Yes you could also try and remove the hose and cap the valve or port at the manifold for testing. Flooring it would in theory completely open the valve and then when releasing the accelerator if the valve were to stick open may mimic the effects of a vacuum leak and induce the rough idle.
Ive done this plenty of times (with the cold engine light off) and have not had any issues nor do i have any concerns with the practice, the rev limiter does a great job at protecting the engine.
Dependent on whether or not OP has a MAF sensor this may not be very accurate