Re: how should i aproach my 4th kyu test?
Most dojos and federations have lists of techniques that are required at different levels. I'd suggest reviewing these but not focusing on them in preparing for your test (because as Mario says, there's no rule that says that your test won't go beyond that). Learn the terminology enough so that you're not standing up there saying, "Huh, what's that" when sensei calls out a technique, but don't spend an enormous amount of time on this either. Rather, I'd say focus on the fundamentals that underlie good technique. Every sensei has a different way that they talk about these -- mine tends to talk about "when" being the most important thing, "where" being next, and "what" (all those techniques on the list) being last. So, my sensei cares more about how good your timing is and how you get to the opening, than what you do once you're there -- the "what" still matters, but it needs good timing and proper movement to be effective. Your sensei's favorite fundamentals may be different --, now would be a good time to start listening closely in class and discover what they are. Your aikido classes are more than a string of techniques -- start paying attention to the principles that your sensei is stressing, and work on developing them in your practice so you can demonstrate them on the test.