datum: I'm ND, but I'm a good test-taker. There were plenty of tests for subjects where I didn't need to study because I was adept at reading the question and correctly assuming what the test-creator wanted answered, and using deduction to reduce possibilities down enough that I could be certain of an answer - or by using meta-knowledge of where the material from the recent lectures was to narrow things down, again, not because I knew the material all that well but because I could read the question. Effectively, I had a decent grasp of the "game" of test-taking, which is rather orthogonal to the actual knowledge of the class material.