That would invalidate all solutions ~~

Hurray, in that case I am going to reimagine my much-less-elegant-than-the-winners solution as an "extra credit" solution.

Doing that would honestly increase the difficulty of the kata, simply because users would not only have to memoize the proper values that added up to the sum, but also the indices they were found in.

Consider that an "extra credit" problem ;)

that would be "more precise", yes (about the way the tests or done). Tho, considering how old the kata is, it would be unreasonnable to change the specs now, while the current contract is still correct (even if it could allow some weird stuff to pass from time to time).

cheers