Do you think I can pass a pee test?

I've been clean for two weeks haven't smoked even though I'm sitting on a half. Taken Niacin everyday, drank 6-8 cups of water, and lots of beer. I got a detox drink but I'm thinking if I should even use it or save it for once I do get this job in case they pop a random test up on me.

Oh and weight 160, 5"7' not much body fat but some, probably 15-20%