Are you going to pee right infront of your boss? Probably not, find someone a couple of people who you can trust that are clean and havent smoked, and just to be safe test a small sample, if they pass put their piss in a ziploc bag and put that into another ziploc bag.

go to the bathroom pee in the cup to make the noise pour it out in the sink and then put in your buddy's piss wash your hands pour the rest of the piss in the sink, maybe want to bring a 3rd baggy to put the 2 dirty ones in and just put that in your drawers or something...

my best suggestion if you still test positive the day before the test