Do practice tests usually match what's in the prep books?

I'm studying for the HiSET, and the stuff I've learned about so far in the prep book doesn't show up at all in what I'm pretty sure is the most recent practice test (FPT8).

I've never had to study literally at all until I decided to do this, so I'm not exactly sure how these things usually work. Is this normal? What will actually be on the test in that case? Sorry if this is a stupid question, I want to know what to prepare for.