The VAST majority of drug test wouldn't waste their time. They search for mass abused perscription drugs, crack, meth, cocaine, and marijuana, of course.
That i know of, they can only be detected by specific psilocybin tests that police stations dont have on hand. Apparently they are really expensive to get, and unless your dealing with the feds who have a suspicion that you are on shrooms or something, I dont think you'll run into any problems haha. And yeah i think its out of your system pretty fast as well.