i dont. but i used to.
i was testing pills when the tests werent as sophisticated as they seem to be now. i remember getting results that could tell me if there was mdma in a pill or not, and even if there wasnt, i still dosed the pill. quite frankly, i paid $20 for a single pill, and whatever drug was in it, i was going to enjoy.
things have changed, and i'm lucky enough to have found sources that i know to be reliable and somewhat honest.
on top of that, and i know this is debatable, where i'm at, e is almost always sold in pill form, and most people who have pill presses put at least some mdma in their pills. maybe i'm just fortunite, but even when i was buying pills from random strangers in raves, i almost never got ripped off.