New job, safe to smoke?

So over the past few weeks, I have gone through the interview process and have acquired a new job working for a large office chain supply store. I cleared the background check a week ago after going through interviews with the assistant manager, general manager, and district manager. I was officially offered the job while filling out my background check paperwork, and my training starts in roughly two weeks while I ride out my last few days at my current job. Now over the course of these weeks, at no point has there been any mention of testing as part of the hiring process, but through internet detective work it is not uncommon for this company to test, but it seems to be location specific. However, most of the testing seems to go on during the interview process/background check. I have not smoked in about two months with regular exercise and weight loss, so I know I can pass a test right now. Do you think it is safe to finally celebrate the new job and spark up a fatty, or wait until I officially start getting paid by the company?