It is probably easier to just rewrite the expression every time instead of trying to change it for your hypothetical legacy support case.

Out of habit I think.

For a little added complexity, why not have some negative products thrown in the mix?

Good work ;)

Random tests seem to expect empty arrays instead of final merged results.

I would like if the description stated if the list is ascending or descending sort. Other than that, I enjoyed this Kata.

You are absolutely correct. That is probably a case that should be in the tests.

greetings is not a defined variable in the given test cases. This causes the test cases to always crash. I worked around this by adding GreetingsMyFreinds greetings = new GreetingsMyFreinds(); to every test case. The class name of GreetingsMyFreinds is spelled wrong and should be GreetingsMyFriends. In your description, "this" is spelled as "thit." The error messages upon failing a submission are not very helpful as they read arrays first differed at element [0]; expected: but was: when I was missing an "!" on the end of my strings. Just a few things that could be cleaned up. Otherwise I didn't see any issues.

I think a coffeescript test case is broken. Specifically the one that gives 59948945969459 cents. My answer was:
{ '1': 4, '5': 1, '10': 0, '25': 2397957838778 } which appears to calculate out to 59948945969459 just fine. However, the test says I am wrong and it was expecting {"1":4,"5":1,"10":0,"25":1366087610} which only appears to be 34152190259 in value.

I encountered no issues with it. My solution worked quickly and without issue.

I was getting that error as well, but then it went away. Not sure what happened.

I was getting flashbacks to college while working on this one. Interesting problem as well as learning about how things work inside computers makes this a neat Kata.

Nice!