Precisely, excellent point. And if all I can keep is the feeling of a ominous, uncertain problem, I will try to keep it that way :)

Care to give something more specific about the broken test cases, including language, input and wrong output that passes it :)?

And, as I mentioned, the goal in this kata is also to give some ambiguous direction to see how users manage to figure it out by themselves: I don't think I have done it elsewhere and I wanted to keep the interview feeling that I got getting this in an actual interview - that's all :)

Do all solutions get re-run after changes to a kata's tests? Are points revoked for newly failed solutions?

Kata writing and solving should be a learning process. That kind of cheat solution serves a valuable purpose because it points out weaknesses in the tests.

Typo on my part. I changed the test output to read:

add2(x,y) { return x+y; } ; add2_ = defaultArguments(add2,{y:9})

Makes more sense?