It was me. I've got the test too. The work is actually for RaterLabs. Appen is to RaterLabs what MTurk is to Hannah Rashkin. RaterLabs is just a requester and I think this is a new project for them, since the guidelines for the task aren't even up yet. So, unfortunately, I don't think we're going to find much usable prep, other than doing the same type of stuff daily on mturk. But, you'll have 6 days to study before taking the test. DM me on Monday, if you want, and we can study/compare notes, etc(if that's allowed. We'll know more when we get the Guidelines).
But, yeah Appen has as many varied tasks as Mturk, from various companies
https://talent-appen.icims.com/jobs/search?ss=1. So, if anything, I guess you could ask around and see if anyone has done any work for RaterLabs. Good luck!