For checking users' solutions, you can try this: https://www.codewars.com/kumite/579d80d97cb1f385ed000231?sel=579d80d97cb1f385ed000231
I did it another way in a different kata though, so let me know if this doesn't work.

That really just depends on how you write your solution. You're right in a way though; they're not necessary, but could help someone get some ideas to form their answer.

I shortened the description a bit and gave the sections some headers; it's still long because of displaying the patterns, but hopefully it'll help others.

OK, I removed the invalid input tests section; also, removed a bunch of tests that, on second look, weren't providing much value. I left in the tests that demonstrate different truthy/falsey values, even though there's a lot of them. I probably wouldn't do this again in future katas, but I figure someone might learn something from reading through them.

Oops, didn't mean to submit this one.

Fair point; I'll see if I can reduce the description length somewhat.

Looking into it. Thanks for the feedback!

Thanks for the compliments; hmm...I thought the prompt was original (if not so much ways to solve it). :(

In the description there's a code block with a couple examples of errors that should be retained, including:

THIS(Infinity); // RangeError

Is that what you mean?

Your implementation doesn't actually need to explicitly throw a RangeError given Number.MAX_SAFE_INTEGER. You can see it still passes commenting out !Number.isFinite(n) ||.

The idea behind testing for the errors was to avoid solutions that just say something like else return 1 level of THIS.

I agree there are A LOT of tests going on, but would you change your vote given some specific change?