I think I had to do that at my school last year. I forgot to wear a tank top or 2 piece like they said, so I had to do it in my uniform.
I remember the girls in our school had their test done by a man-like lesbian. Anyways it is a 10 second test half the time they don't even touch you. They tell you to bend over and then you are done.
I have Scoliosis. Got my test last year. It isnt tht bad but i wont describe it cuz the way i do it might sound a little odd haha