looks like code written by someone who doesn't want to get hired or work in a team :)

I'm trying to figure how can I improve on "Sample tests should contain examples of invalid input."

from a definiton of other functions you have a point, from the purpose of the function, to return the number of seconds a video is playing, -1 suggests somebody has a time machine and can go back.

The idea is completely uninspired. Feeling like trolling or did you forgot how it is to be a beginner?
The idea is completely inspired as it comes from real requirement from real project that I or my students encounter at work.

I'll revise regarding input validation. Thanks for your time!

Good pointers! I'll revise.

(123) 3 + (space) 1 + (45) 2 + (space) 1 + (6) 1 = 8 chars, which is greater than 7

Love one line solutions!

Another one-line-solution makes me happier and happier.
I'm getting better at this :).

It might be useful to try using a different approach.
I usually take a five-minute break that must be a real break, no coding thoughts passing through my mind and try again.
Repeat until successful.

I just love when I can solve it in one line without variable declaration.
Anyone else feels the same?

I can start my own editor now! Here I come!

The title of this Kata scared me.
I've almost skipped it until I've gathered some courage to face it.

This scenario is a reminder why I love regular expressions.
RegExp to the rescue!

I've completed this kata and it passes lots of my tests, and all of your tests but the first one.
You really have to be more descriptive in your kata as there is a lot of amibiguity