Nice done, thank you @FArekkusu :) (even if this invalidate previous solutions ;P)

Submitted my own solution. All works now.

I have fixed the reference solution. Please, reset the trainer and try again.

@stɛffan153: actually JS random tests produce input of length < 4 and expect result of length 4 :(

I'm totally agree with you... that should be stated in the kata description and better if minimum length 4 is required, expected result of input such as [ 0, 1, 0 ] should be [ 1, 1, 1, 0 ] but not [ 0, 1, 1, 0 ] as it is actually ^^

It doesn't need to be of length 4. It needs to be of whatever length that the array passed in was.

Kotlin's tests were subject to input mutation troubles, and expected/actual where swapped in the random tests.

Handled. Hopefully that will be enough.

Can you pass me a fix, possibly opening a translation?

I have the same problem in Kotlin and I was so proud of my solution too :( the order of assertion logic seems to be mixed up for kotlin.