Well, seeing as I LOVE all these rides (and about 95% of all the rides in WDW for that matter....haven't tried the water parks or the new FL yet XD), I'll add my 2¢. I might end up repeating most of what everyone said already, but oh well. I'm in a talking mood.
Test Track - I haven't ridden the 'reimagined' one yet, but based on what I've seen/read, it's the same general advice I'd give either way. There are some dark parts in this ride (including a moment when a truck tries to surprise you in said darkness, but it's easy peasy lol), but the part that most people like about this ride is outdoor portion. Like a PP said, it's like riding in a convertible on the highway. It's truly nothing to fear. Besides the truck, nothing comes out and scares you in the dark, there are no big drops, nothing that would give you fright. You'll be just fine on this one.
Space Mountain - this one can be a bit more intimidating, especially because it's mostly in the dark, apart from the beginning and end. If you don't mind seeing the entire track layout, watch this video. It's Space Mountain with the lights on, so you can see the track clearly and know exactly what to expect: (
http://www.youtube.com/watch?v=ygYP8C6QhC0). This video was before the refurb, but the track never changed, just the effects, so this is what you'll get track-wise. I think of it as one step up from Primeval Whirl in terms of drops and track layout. The dark and sound effects you hear are meant to make it sound more thrilling, but really it's not bad at all. It does whip you around a bit, but it's nothing too horrible. I've been on MUCH worse, so I wouldn't worry about it. It's too iconic of a ride to miss out on IMO, and even if you end up not liking it, at least you can say you've at least given it a shot.
Mission Space (green side) - a piece of cake. If you were to suggest orange, then I would give more caution, but green is tame. The only thing that would worry some people is if you had claustrophobia. It closes you into a pretty tighter space than you're used to, but there's a screen right in your face, which is where your focus will be 90% of the time. No need to worry about the darkness in this one, because like I said, the screen is all you'll really see. This one is also pretty tame, so you'll be fine IMO.
Dinosaur - out of this whole list, this is the one I'd give the most caution to. There are no drops (if you ever feel any, that's just the ride vehicle jostling you around for effect), but it's 90% darkness, with the only parts lit up are the beginning, end, and the dinosaurs right in your face lol. It starts out tame, but by the time it ends, a lot of people end up screaming and kids can get frightened because of the dinosaurs and loud noises. This is another ride I'd recommend seeing online before considering riding (link is here

:
http://www.youtube.com/watch?v=uUazcYyJn4w). There's no video around that shows exactly how the layout is, but night-vision helps a lot. If you aren't afraid of dinos and things of that nature, then that'll help, but again, the darkness and loud noises tend to even scare some adults, so I'd think about it.
Personally I love ALL of these rides, and I used to be afraid of Space Mountain when I was a kid. Once you ride those rides and know what to expect, it's not so bad. Might as well take advantage of the rides while they're still here with us. Space Mountain I don't see going anytime soon (just because of the nostalgia and how popular it still is), but better to try them out and say you have rather than not and regret it later when it's too late.
Tower Of Terror btw can be pretty frightening for some people (my niece actually sobbed throughout her entire first ride, full-out-screaming kind of sob, while her brother half her age was perfectly fine with it. It all depends.

) The only thing it really truly does is lift you out of your seat a few times, and while in the dark, you get a gorgeous view of HS and more of WDW.
Rock N' Roller Coaster is a totally different experience all on its own, so I won't even try to delve into that topic. I know you didn't ask for it, but that's just FYI.
