An invalid input 'ㅉ' was given as final consonants in random tests. As per the linked article on Wikipedia (https://en.wikipedia.org/wiki/Korean_language_and_computers#Hangul_in_Unicode) 'ㅉ' is not part of final consonants.

[ 'ㅁ', 'ㅖ', 'ㅉ', 'ㅋ', 'ㅒ', 'ㄱ', 'ㅌ', 'ㅚ', 'ㅎ' ]
[ 'ㄴ', 'ㅑ', 'ㄴ', 'ㄲ', 'ㅡ', 'ㅉ', 'ㅈ', 'ㅚ', 'ㅈ' ]
[ 'ㅌ', 'ㅔ', 'ㄶ', 'ㅉ', 'ㅖ', 'ㅆ', 'ㅊ', 'ㅐ', 'ㅉ' ]

These are not valid Hangul compositions.

Interesting kata anyway! Really enjoyed the challenge :)

thank you! I've fixed that now, and thanks :)

It doesn't make a huge difference, but the array in the first test case has 8 elements instead of 9 (missing a "" at the end).

Good kata!

Thanks for the heads up on this. I've fixed the problem by changing the random test fixtures.
The problem was with the way I was generating the random tests. The test suite won't test for actual korean words anymore, but it won't expect NaN either :)

It seems some random tests are expecting "&#NaN;". eg :

arr = ㅇㅘㅇ ㅅㅔㅂ ㅜㄴ
✘ Expected: '왕셉&#NaN;' <-- NaN ???

Is this really what you're expecting ?

Thank you! I've fixed it.