I would imagine this would depend on many factors, mainly, the state this taking place in. For a better response, include the location as you may find someone who has gone through the same thing in the same area. Good luck with it all.
In GA they hair test. Happened to my sister and a coworker a few years ago. It is COMMON only in family cases...they don't hair test for felony or misdemanor prob just piss test. So you will fail unless you shave your head/all hair ALL over your body and regrow it in the meantime.
If you want to pass a drug test, Coconut Shell Activated Charcoal.. I've done it... Its takes about 100 capsules, but its easy to swallow, four capsules is a gram. Drink a ton of water and you can take it over a course of a day as long as you Dont smoke again.