On such a contract they cannot COMPEL you to test, and they probably will not. But, understand, that if you fail to comply with a request they CAN still submit to the DA for prosecution. Whether they will or not is another question. And since marijuana reeks and stays in hair and clothing for an extended period of time, it is likely that at some point a PO or an officer is going to smell it on you and this request MAY come up.
Note also that if you get caught with marijuana or paraphernalia that can and probably will violate the contract as well as grant you a new charge.
It might be a good time to get clean and sober before it becomes an issue.

