To be honest, I myself have taken a drug test on Monday after smoking Saturday night and passed. It really depends on your body. It you barely ever smoke you have a decent chance of passing after two days IMO, but I'm just one fairly stoned man. It was similar circumstances too, I had smoked a small amount of bad weed with like 4 other people. I felt pretty high but I still only got like 3 hits. It's probably a crap shoot, but I've done pretty well with those odds before.