Short for "Rub-one-off test". This is a test one must take in order to realize if a female prospect is really worth dating. The males mind can be often drifted away by lust, but we realize our drunken mistakes immediately after sex. To prevent this from happening one must masturbate then ask ones self "Do I still feel like being around this broad?"
If so, then the prospect has passed the roo test.
Matthew: "Hey look at that chick over there Johnny? She is so in heat! She invited me back to her pad so I probably wont need a ride. I might even keep this one!"
Johnny: "Woah Woah! Hold on bro that chick is busted. How much you had to drink? You might wanna take a roo test on that one my friend. Dont want any regrets."