To create a truly stable strain could take 8-9 generations. Or 8-9 years or if growing in hydroponics it could be acheived in say 2-3 if your lucky.
Good accurate testing requires good accurate $$$ and the ones in the "hobby" of growing chilli's usually have little to no interest in getting peppers tested. I have seen tests available for $50 HOWEVER they are about as useful as tits on a bull in terms of getting numbers that reflect what the pepper is achieving in relation to it's SHU rating. It's like getting a tattoo, cheap ones are shite.
If growing commercially it makes sense to get XYZ peppers tested so you can claim the record, sell seeds and or plants for a while before every man and their dog has seeds and hopefully make bank in that short amount of time.