I have a drug test tommrow for work and kinda nervous!?

So i havent smoked pot since march and i am doing a drug test tommrow at my new job, but they are doing the test with Gauss where they put it in your mouth and let it sit there for a bit. I havent smoked since march 2009, will i be fine, or am i screwed. How long does it take for marijauna to leave your system?