Yeah they have multiple tests and they can vary in difficulty but are usually the same topics (3, if i remember correctly.)
I'm pretty sure they're going to quiz you on the last 2 or so terms, but be prepared to study for term 3 topics ( I did the test pretty much this time last year, and I got logarithms among 2 other things which I forgot.) In terms of resources, you should do the chapter review for subjects you've already learnt and go through the cambridge chapters (maybe not fully - e.g. every last column of each question) which you think may be on the test.
Some advise for du:
Don't worry if you don't get into a2 because the kids in a3 are kinda dropkicks, and the tests are pretty easy so long as you finish the homework so it's very possible to move up in your first term. Also, from second hand experience be wary of big Du (he teaches poorly), as well as his son who has a very unique teaching style. Charles et al. and the student teachers are usually great, though