Here in NJ, the answer would be yes. If you think you would fail this test, talk to your lawyer before the situation occurs. Good luck.
This information is offered for informational purposes only, as I do not practice law in your State. It is not intended as legal advice and you should not rely upon it to decide how to resolve this issue. No Attorney-Client relationship is intended or established by this response. You are faced with a situation where you need to consult with an experienced defense lawyer admitted to practice law in your State before you make any decisions as to how to resolve this issue.
Part of every probation in the State of Texas is something along the lines of "commit no offense against the laws of the State of Texas". It is illegal to possess drugs and your probation officer can order a drug test pretty much at will. With a new arrest, I'd say it's pretty much guaranteed that you will be drug tested some time soon. You obviously need to stop using any and all illegal drugs and continue to do so while on probation.
Talk to the lawyer that's doing the walkthrough for you for more information.
Of course they can. You are on probation and any violation of the law is a ground for revocation. Another common term of probation is that your person can be searched. That includes blood urine and DNA samples to name a few.
You say ou're represented. You need to talk to your lawyer. This isn't legal advice, so don't rely on it (especially since I'd need more information before advising you).
A probationer can certainly can be tested -- at any time -- while under supervision. The new warrant and arrest will also give them reason to test the person if the PO is on the ball. If the new charge is drug related then it's a no-brainer.
Sometimes they even wait a couple months, trying to fake out the probationer.
You need to bite the bullet and keep you nose (etc.) clean while you're still under supervision. You may think it only happens to someone else, but you could be the next new resident at the correctional complex.