Can someone drug test you without consent for nonmedical/ employment purposes?

I don't do drugs, but my boyfriends mom is psycho and thinks we're both on drugs even though i work full time and go to UC irvine and give her absolutely no reason for suspecting me of any type of drug use. Anyways, she started going on a rant and started following me around with scissors trying to cut my hair for a drug test. I told her that I didn't want her to cut my hair, and I left. I know that she could easily get my hair from my hairbrush at her house, so I'm wondering... IS IT LEGAL FOR HER TO DRUG TEST ME WITHOUT MY CONSENT? I feel like its invasion of privacy, so I was just wondering.