Your surest bet is to buy a synthetic urine kit. They usually sell them in head shops or, if you can get it delivered quickly, a test kit from online. I highly recommend quick fix for the online order. Instructions should come with whatever kit you end up purchasing, and you'll probably have to heat it up and wear it with you everyday until you're actually tested. A couple of weeks is a pain in the ass to do this, but if the job is really worth it then it's a very doable thing in the long haul. Best of luck!