If it's weed and a piss test, then just buy a bottle of Ready Clean, or whatever other detox kit they sell at your local bodega. I was being piss-tested weekly a few years back and passed all but one test. The one I failed I smokes 18 hours before the test. I passed multiple ones after smoking 20-24 hours before. As long as you take a day off before the test, and use the stuff as recommended, you'll be fine. It's usually only $20-30, and I am telling you from first-hand experience. No need to drink your own piss or carry around a bag of someone else's. Besides, some of the testers stand right in the stall with you, and there's little room to maneuver. PEACE.