I don't know of a website to host it that has a multiple choice quiz option that will tell you your score, so you'll just have to do it in the app. Like the rice purity test, count up each item you checked off, and minus your score from 80.
For each item, check it off if you would do it, have done it, or the idea of it turns you on, in a fictional or realistic context, with fictional or realistic partners.
Have someone touch my belly
Stuffing (eating beyond the point of fullness)
Post-injury healing weight gain (includes eating disorder recovery)
Body contrast/size difference
Look at weight gain art, sequence art
Look at before and after photographs of weight gain
Break clothing (popping buttons, ripping seams)
Lay underneath someone heavy/on top of someone light
Burp in someone's face/have someone burp in your face
Soft, fat, flabby bellies
Fatpads (the layer of fat over the pubis bone)
Too fat for certain sex positions
Too fat to fit in someone's arms
Too fat to reach yourself
Oviposition (pregnant with eggs)
Soft vore without digestion
Hucow (human cow transformation)
Monster transformation weight gain (like werewolves)
Secret weight gain manipulation
Bimbo/himbofication through weight gain
Eating on all fours/eating with no hands
Double your starting weight
Unrecognizable weight gain
Extreme weight gain (500+ lbs)
Unrealistic/fantasy weight gain
75-40: occasional fetishist
39-1: dedicated fetishist
(disclaimer: score results are a joke. Purity can't be measured, this quiz is not comprehensive, and as long as you're having fun and not hurting yourself or anyone else, it doesn't matter what you personally would or wouldn't do for the sake of a quiz score)