What on earth is the point of an input of length 100_000?

It adds no performance restriction and only serves to make displaying the inputs more problematic for the user.

Speaking of, white kata need assertion messages.

That's an issue, not a suggestion, and it's documented here.

Please read all applicable documentation, and test suites of your solved kata, and learn from that. ( If you solve more kata before publishing your own first kata, you could probably learn more from them. )

Use built-in python integer division. And report a wrong case if it happens, not what you think could happen.

Python random tests generator has a protection against generating division by zero in the expression, and there is no fixed test with division by zero either, so...

you're not saying that the tests generate such a case. you're not using those words. if it does, that is an issue. you're being vague about where 3 4 9 / / comes from, but I'm guessing you came up with it. which means it didn't happen in the kata. which means there is no issue to report.

an issue needs to demonstrate the problem in a reproducible way. tbh, issue reviewers will probably dig more than they're willing to admit, but if your issue is incorrect and you're sharing something that's multiple steps of reasoning away from the bug itself, then the person reading your issue is not going to be making the same mistake as you and thus won't encounter anything being wrong and will therefore not "get it".

I'm guessing your code divides by zero. cool. go debug it. start by finding out what input your code fails on.

I prepared for this kata by reading about the Postfix Mail Transfer Agent. Only after doing that did I read the kata description :P

I guess I already explained it up there, 2 / 3 with integer division is 0, 9 * 4 is 36.

3 * (4 / 9) = 0 using integer division. Please check your math.