Adaptive Test is the way to go.
I took it a few days ago and didn't pass it by one question. Turns out I should have passed it because one of the questions I had to edit a user and give him a home directory, but it wouldn't let me type in his directory! I asked the guy and he's like, "that's the way it's supposed to be." I'm like ok fine, hopefully i'll pass anyway, but that one damn question screwed me. Afterwords I took it to an instructor and he said that I was supposed to be able to type it in and I got screwed, but there is nothing I can do about it so i'm going to have to go back and take it again :|