school drug testing

hello everyone. so i found out July 18th that im going to school! so i quit smoking that day… im a fairly heavy (2-6 bowls a day) , and have been smoking steadily for the for past likeeee 3yrs. on & off before that … when i quit smoking in July, my supply was low, so i was smoking a bit of wax & resin, and like MAYBE a small bowl a day at that. so im not exactly sure when ill be tested is the issue (it’s only a 4month program so Aug-Dec) … so i dont really wanna carry fake piss with me EVERY DAY and try to keep it warm (if i can get good advice on that, maybe). but i’m really wondering, what should i be doing to get it out of my system?? i’m a female, 5’4, 20yrs old, and like 170-180lbs. i work fast food as a manager, so i sweat fairly decently especially with it being hot outside rn. im drinking a lot of water & starting to drink cranberry juice. i just got airpods, so im gonna start walking in the morning, or after work. but any advice how to get it out of me lol??!! also do i have a good chance of being clean by like sept?? cuz i assume, as of rn, id get tested around mid-Sept-October or so. i couldn’t imagine it being during the first month of school … id love ANY & ALL help/advice/good vibes. thank you !!