Is there any way to distinguish result strings for valid and invalid inputs? Something like how Haskell has Left "invalid ID" and Right "12345" ?

Searching return values for the substring "invalid" does not feel like good datatype design.

check_url("fttps:/BlahBlahBlah.com/2163")-->"fttps: is an invalid protocol."

"fttps:" isn't the protocol, "fttps" is. This makes "hs/UL.com/4" very weird and definitely wrong.

The colon is not optional, but that doesn't make it part of the protocol.

This kata has nothing to do with actual QR code, which is an established term with a well-defined standard. It should be renamed to something else to avoid confusion.

1. All the sample tests are still wrong.
2. In the actual tests, the input is an array which contradict with what is given in sample tests.

random tests are subject to crafty exploitation and cheesy manipulation by the user

The task is already covered by https://www.codewars.com/kata/544a54fd18b8e06d240005c0