No, but if you own the game and have an account, there is a way to participate to beta-tests of new patches. You just run a different exe file.
I think there is always WoW Free Trial in every Blizzard games...(Diablo II, SC, SCII)....
Yeah, I got two with SC2, one from SC1 battle chest and I think another in WC3. However, it only contained a 10 days subscription, not the entire game.