fuck you. thats complete bull shit.
from experience, this is what works:
keep drinking a lot of water. And right before the test, just chug as much water as you can... The water will literally pass right through you so youll be fine... and for a few days before that, layer up and wear heavy sweaters and pants and just go for runs and sweat as much as possible.
guarantee youll be fine...
dont try to sneak other peoples pee... there are usually police officers in the bathroom that watch you.