can someone please explain, how i should get another 2 element from test for knowing out is there any interesting number?

Not all languages (eg Python) test for Unicode-only characters, and instead only test for Ascii.

JS, maybe others:
Literally a single random test. Just the one.

WTF?
expected 'G' to equal ','

I want to see the test case that fails! I don't know what to fix! :(

Lua translation!

suggested edge cases that a first version of my code did not handle correctly, but passed anyways:

• trailing empty column:
  • "1,2,,\n3,4" --> [ [ '1', '2', '', '' ], [ '3', '4' ] ]
  • "1,2,," --> [ ['1', '2', '', ''] ]
• trailing empty row:
  • "a,b,c\n" --> [ ['a', 'b', 'c'], [''] ]
  • "\n\n\n" --> [ [''], [''], [''], [''] ]

Python (at least):

Random Tests are not guaranteed to fail a faulty solution such as this one that fails to account for upper / lowercase counting as the same char, as shown the 3 test cases below.

input  ' iwDwW59viI;LMxADnEc5XMCVVrX3hp0u '
result 'W' should equal '9'

input  'f.FGP1.H59u n3'
result 'F' should equal 'G'

input  'peLiEWOfbS,Brl1PsUcBgmaRnMShh5q8osKoyziKTvjv'
result 'E' should equal 'W'

What's meen testUpcomingBigNumbers
It's last crash test, and i don't understand how will make correctly

• JS Node 18. should be enabled

• decodeURIComponent function is not mentioned anywhere

Rust translation

should handle for solutions like this

C# initial solution setup is missing relevant imports

using System;
using System.Collections.Generic;