Approved

In what language?

Apparently, yeah 🤷
I even managed to submit a working solution :D so that's probably why I didn't notice.

Approved

Vandalised only slightly, and approved.

Uses assertions with better failure messages.

Approved

• Moves info about types to solution setuo,
• Makes test sizes progressive,
• Changes assertions to ones with (hopefully) better feedback.

Merged

Fixes tests calling user solution as reference solution.

Rejecting due to:

• no random tests,
• unnecessarily complex setup with a class.

Rejected due to not using decorators, and excessive golfing.

Are you maybe present on Codewars Discord? We have #fixing channel there dedicated to discussions on fixing existing kata. If you are interested in fixing/improving C# tests, there is for example this ticket.

Vandalised and merged.

UTF8 is a variable width encoding, and std::wstring does not support it out of the box. Arguably, "narrow-char" std::string can be more suitable for handling variable width characters than std::wstring, because it can make handling of characters encoded on three and four bytes, and strings with mixed lengths of encoded characters, easier in some ways.

Whether UTF8 makes sense for this challenge or not is a different question. I do not like this either, and I personally would go with std::wstring and UTF-32 (works on linux, but not portable), or, if the simplicity is the goal, then maybe UTF-16 with inputs limited to single code unit characters.