"Teacher's Edition" for tests

I'd like a feature that could be turned on/off that would show the correct answer in either another color or font. I suppose best of all would be a red asterisk, rather than messing with the test.

When I'm in development I want to be able to quickly pass/fail a test. Then, when I want to see the "Learner's" view, I could turn off "Teacher's Edition" and then see it normally.