It all depends on the judge assigned to your case. In some jurisdictions, you will only get drug tested while on pretrial release if you are charged with a drug offense. However, in other jurisdictions, you will get random drug screens for any felony offense. You need to discuss this issue with your attorney.
The same answer goes for whether you will get violated if you "only" test positive for THC. I have had many clients go to jail in Butler County who tested positive for THC. However, those cases were all in front of one specific judge.