When is your test, and when is the last time you smoked? If possible, simply stop smoking at least 48 hours prior to the test. Of course, the longer the better. Saliva testing does indeed only detect the past 48 hours or so. If you're still in doubt, or do not have adequate time, brush, floss, and rinse with mouthwash the day of the test. Do a really good job of it. Then suck on Altoid mints up until the test. If they ask you if you've used breathmints today (which they usually do) then just say no. If you've been clean for a few days though, then your in the clear. No worries.

My friend was getting hired at Kroger and was absolutely freaking out about the saliva test because he had smoked 6 months prior. I did some research and found out the detection period is only like 48 hours

Good luck.