Having been drug-tested many times, basically you don't have too much to worry about.
#1, they usually don't force someone to watch you pee. They usually give you a cup, send you into the bathroom, and then they verify it once you've come back to make sure it's the right temperature and everything to verify that it's not a forged sample.
#2, if it's any consolation, drug testing is usually done by 3rd-party companies, so even if someone does insist on coming in, it won't be with the people you'll actually be working with, it will just be with some random lab worker that you'll never see again.
#3, they do not test urine samples for hormones, just for the presence of opiates, marijuana, cocaine, PCP, and various other drug-related substances. These are all specific tests. They're not doing like a doctor's spectral analysis where they'll be able to tell EVERYTHING that's in your body.
#4, they might actually just do a hair follicle test. That's becoming a more popular method of drug-testing recently, because it's impossible to forge samples and can test for the presence of drugs for 90 days back, possibly more. In that test, all they do is snip off 50-70 hairs or so, and you're done.