can i pass a swab/saliva test?

Que pasa? Here's my problem,just got hired todayand warned that Mon. or Tues. I'm having a saliva test done (wasn't even aware they existed), and will be tested on-site randomly in the future. I've been smoking herb about 13yrs, nearly daily (approx. 2spliffs/day or less,high test Alberta bud). If I dont smoke for the next 4-5 days until the test am I still getting busted? I'll be working 6 days a week,so I'm also wondering if I'll be able to blast a couple on Saturday night and not get caught on Monday if they walk up to me w/ a test in hand? Anybody know any cheats?Do I even need any?I'm stressed and would really like to make a decent wage and not have to give up herb.Thx.Legalize.