Using fake pee or pee from a clean friend
This can work. Some fake pees come with heating elements to get them to the appropriate temperature, and hand warmers also can do the trick. The key to this technique is scoping out the space where you'll urinate.
When I was on probation, for example, I peed in front of a female employee who looked in at me from a little window behind the toilet. For a job interview, you may have access to a private bathroom, and if you don't, think very, very hard about how badly you need that job.
Gerhart says using fake urine is a dangerous game. "For as many stories as there are of people who beat a test by doing that, plenty have gotten caught doing the same thing," he says. "I heard about one fellow who tried to back-fill his bladder with dog urine and a turkey baster. Creative, but not a good idea. He wound up in prison with a horrible urinary tract infection."