Nice kata!

Julia translation

Haskell translation

I have added some for the Rust translation, but ran into an issue with the enormous size of the return values, which I've listed them above.

If such tests are acceptable, I can update the JavaScript version as well.

Rust translation kumited.

• It includes random tests, but due to the returned String increasing rapidly in length with n it is limited to [0, 39]:

  n	10	20	30	40	50
  String length	82	1 278	19 018	271 102	3 842 984

• I used None instead of -1 for n = 0, as the former is more idiomatic in Rust.

No random tests.

Very nice kata. I liked to solve it, I got a lot of fun!:)

The kata is very fun, but the interface of the given function is poor. Since Swift is strongly typed, the interface should make use of that instead of allowing users to pass a nil as the argument.

Why 62847?

There's a typeo in the test cases when you test getLines(5). And really you should just convert all of the tests over from Test.expect to use Test.assertEquals instead. Like this:

Test.assertEquals(getLines(5), "1,11,21,1211,111221", "getLines(5)");

The Test.assertEquals method already has all the built-in logging to give a helpful message. E.g.

getLines(5) - Expected: 1,11,21,1211,111221, instead got: (something else)

or

Test Passed: Value == 1,11,21,1211,111221

It's a typeo. It should say "getLines(5) should return (5th line), instead got (what your solution returns)".

if you have the array then you have the comma separated list (arr.join(","))