Re: What's it like on a exam...
It's different for every dojo -- I could tell you what it's like at my dojo, but that wouldn't tell you what to expect at your dojo. Ours tend to be pretty long, and if it's a fifth kyu test, Sensei will also ask for most of the fourth kyu techniques and some third kyu techniques as well. I'm not entirely sure what he's looking for in that (maybe it's just for his amusement). It's moderately strenuous and some people find it fairly stressful, and then it's over.