There should be more random tests for odd number of digits to avoid solutions like this.

Javascript:

Couple of conditions mentioned in the description are not checked in the test cases

1. no test checks for a 0 length string - description says should throw an error
2. no test checks for an illegal character at the mid point in a string with an odd number of characters - description strongly implies this should throw an error

hello, in prerequisites basic test i have a error "It should give an error for invalid input: True should equal False" but code is fine, all another tests passed. Work with Python, what do i do wrong?

Go translation

Hey, @SandaySalsa! Description and Ruby test cases aren't clear! Or this kata like puzzle, guess what should be: luck_check('6F43E8') == false or luck_check('6F43E8') == 'Error' or end of program :) And luck_check('') in test cases will be an error.

Yours sincerely,
FridayBachata

(Ruby) cannot pass the invalid string input tests (only for submit, test button works). If I return 'error' or false, I still get: "The function somehow worked with wrong input"

"6F43E8"
"Error"
The function somehow worked with wrong input
"1234 "
"Error"
The function somehow worked with wrong input
""
"Error"
The function somehow worked with wrong input

Pretty sure the test cases are broken. Once you get to random testing, the tests expects you to return false on invalid input instead of throwing an error.
Also the description should probably be more detailed about dropping the center character on input with odd length.

It's strange but tests work differently when I click 'Run test' and 'Submit'.
I had my tests failed with incorrect argument when I use raise unless ... but same tests had passed when I click 'Submit'!