We need downvote buttons :p

If you found this little exercise in returning a function outside the box of your normal thinking,
I strongly suggest learning lisp (common lisp, scheme, or clojure). It will blow your mind. You'll
realize what an incredibly poor job modern languages have done in trying to emulate the behavior of
lisp.

In my opinion, tests like this should use an epsilon value to check the result. This would reflect actual real world usage, especially when computing geometric values. Storing the rounded result in a variable makes no sense at all.