I'm not 100% sure what you're asking. If you're asking what will be on a graduate diagnostics exam, it covers what most universities cover in the first 2 years of theory. I just took it a few weeks ago and it had most of the stuff I learned in theory my freshman and sophomore year (yeah figured bass and chromaticism in harmony was on it). But since they're shoving 2 years of theory into an hour and a half, there aren't going to be a junk of questions on one thing (I think there were maybe 2 or 3 questions on figured bass). Chromatic harmony is a lot broader, so I would pay more attention to that (chromaticism covered a huge part of the written portion of the exam for me).
If you have questions about either two subjects, let me know.
I hope this answers your question. Good Luck.