I would not do like the above posts states.

I have not taken the test but this is what someone recommended to me:

Definitely pick up the "ace the tech pilot interview book" if you don't have it, as a lot of the questions on the online test come right out of it. Find out all you can on North atlantic ops, MNPS stuff, and any foreign nuances you can learn about (QNH, QNE, QFE, etc...)

Good luck.