Add random tests (not that I can think of a way to hardcode the solutions to the fixed tests in this little space, but still)

Not an issue o_O If you want help, please post a new question with what you already tried using proper markdown, and don't forget to mark it as having spoiler content.

please hint!!

One line task but i learned much :)
thank you

That allowed my other solution, which is 40 chars. 42 Might still be a little tight - some people will try to solve it as short as possible regardless of the limit anyway, so you'll still see the 37 char solutions. It's a balancing act of course - you don't want to relax it too much.

What limit do you suggest?
changed to 42

If you relax the character limit a little, different solutions would be possible. To me, that would be more enjoyable - I like seeing different solutions.

Done !
Thanks Again

Umm... nope.
Just solve thousands of katas (and view how they do testing) and you will know what to do

Thank you :)
helped me
do you have any source where i can learn these things ? (testing)

No sample tests