schools testing students on outside resources

I suppose they could if they are related to what you have been expected to learn. I have had a couple of instructors do this on occasion (nothing that would make or break you on a quiz/test). Their rational was that we had the tools (based on our current level of knoweldge) to come to the correct conclusion even though we were not directly taught that information. Our ability to choose the correct answer really depended on our ability to think critically. That was the real point of those questions...can you use your critical thinking and what you have learned thus far to pick out the right answer even though I never taught you about this specific problem or the nursing implications associated with it? Hope that helps.

Absolutely!

We were assigned evidence-based journal articles (of course, we had to retrieve them and such). Once in a while, the instructor would spring a "pop quiz" to make sure we actually read them.

It sure isn't unheard of.