Java - random test cases do no pass sometimes.

Ruby 3.0 should be enabled

Should define what is a word and what is the end of a word.

No basic tests in Ruby.

Ruby 3.0 should be enabled.

Ruby 3.0 should be enabled.

Ruby 3.0 should be enabled.

in Java, actual and expected are reversed

missing edge cases: "words" ending with digits -> shouldn't be changed.

Random tests are vulnerable to input modification.

Why literally every kata about bookmaker always has inadequate explanation about the whole subject?

Your "anti-cheat" relies on Function.prototype.toString(), which is totally useless. You should obtain user source code instead.

Even with that, this kata's concept is a duplicate to some existing katas. Even with the additional requirements (that is ridiculous IMO) it does not make this kata new.

I would like to know, in your example of the description, how to calculate 20% ?

I'm getting this error:

Random Tests
Fraction = 7560/3256
[945, 407] should equal None

Both 7560 and 3256 are divisible by 8. I don't understand why the function should return None