Valium is the worst benzo for hanging on. I dropped a couple valium ( when I used ) and 3 weeks later I still tested positive. I knew it had a long half life and I knew it was going to stick around in my urine longer than an oxy would but when i tested positive 3 weeks later i was shocked. So yeah, if you don't have a valid script, delay the test.
Gotta close this as the above poster is kee-rect. We don't answer drug testing questions but since you are probably doing this for a job ( or maybe probation or something ) I thought it best to at least warn you what happened to me. You might be able to eliminate it quicker than I did....your metabolism may be better....but 3 weeks out i was still positive and I had only taken 20 milligrams and I had only taken it once.
So my best harm reduction advice is wait at least 3 weeks and even then who knows? Good luck