If its a public school, it might be a shitty test. If private, it might be some high tech one. I wouldnt try the niacin either. I've been spreading around how I passed a home test wtih a couple drops of clorox bleach. Put your fingers in the bleach and let it dry, now piss on your fingers into the cup. It might not be sanitary, but its what things like the lieing government makes up do. You could also bring some bleach in a eye drops bottle. Empty it/clean it with water first before putting bleach in it, and hide it in your ass or underwear. 2 drops should do the trick, any more than that and it could smell odd.