It's fine I already figured it out. But to answer your question I don't edit sample cases so yes I'm sure I never added those samples.

JS fork (author gone)

complete overhaul with random tests, sample tests, edge cases (1-letter words), chai assertions

i dont see anything in the sample tests. this is an old kata with many issues in JS, it has no sample tests, no random tests, and uses the old Codewars framework. are you sure you did not add those sample tests yourself ? (perhaps long ago; Codewars caches your code and the sample tests unless you click on RESET)

Nevermind I figured it out. It turns out that for whatever reason the "TEST" and the "ATTEMPT" use 2 different function names. "TEST" uses toSnakeCase while "ATTEMPT" uses toUnderscore. Very weird first time I've ever seen this on codewars.

Thank you but actually I didn't rename it, for me it was called toSnakeCase. Renaming it to toUnderscore breaks it and it says this:

ReferenceError: toSnakeCase is not defined
    at /home/codewarrior/index.js:45:6
    at /home/codewarrior/index.js:47:5
    at Object.handleError
        <anonymous>

that's because you renamed the function. it's supposed to be called toUnderscore.

There's an issue with the tests once I press "Attempt". It shows this:

ReferenceError: toUnderscore is not defined
    at it
    at begin
    at it
    at describe
    at /runner/frameworks/javascript/cw-2.js:152:11
    at Promise._execute
    at Promise._resolveFromExecutor
    at new Promise
    at describe
    at /home/codewarrior/index.js:27:5
    at /home/codewarrior/index.js:37:5
    at Object.handleError

I'm using javascript and I have tested multiple solutions even putting them in replit and my solutions are fine.