Testing masks is very specialized and all in I've spent about $250k on the mask lab. I just bought a new machine that costs about $90k. Here's an overview of the machine: https://www.youtube.com/watch?v=vpjajJrDWBk
I think it would be great to have easily reproduceable, low cost test equipment available at shops and clinics because the quality of masks (even of a specific make and model) is likely to vary between units. You might find a good mask with your tests, and then find that your next order of the exact same mask is crap. So you have to keep testing. Maybe it is less bad now. I was interested in this more when masks were in very short supply, but then I managed to get a few boxes of them, and set the testing idea aside.