just basic usage of groups makes it possible to solve this.

that's why i put the term groups in the title.

this is completely done without the use of conditional regex.
(i actually had to look up what conditional regex is)

guess you're missing my point, let me rephrase myself.
The reason your regex passes is because of the \u0020 (which is just a normal space) and not because you are using \t.

There are 0 testcases that contain one or more spaces followed by a tab.

Hope that this makes it clearer for you ;)

it actually has a different meaning.
(putting everything between quotes so the space becomes visible.)
'\t' = a tab, usually used for spacing.
' ' = a space
'\s' = all whitespace characters including tabs and spaces.

No need to say sorry ;)

Take a good look near the edges of the quotes.
spaces at the beginning or end of the phone number string should result in a mismatch.

Marking the issue as resolved.

Indeed in the example test I had them swapped around, fixed that.
Also approved your translation :)

concerning the first bit, I agree it is confusing, but currently I do not know a better way to put it into words. Any help with this is appreciated. Attempted a rewrite, let me know if it is better.

concerning the second bit, Japan and Samoa do not follow the itu-recommendation. So those countries nation code dial out shouldn't result in a match. But I'll update the description for clarifiication.

Updated the tests to correctly mention the expected and actual values. I had them swapped around.

I have succesfully passed all the tests, even though I made a basic mistake of reusing my collection for every run.

So if you would run the same set twice through the same instance in my solution, then the first time you get the requested result.
The second and consequential attempts you'll get 0 as result.

So can I get the loop? yes, but possibly only once per instance.
So if you could change the next node with a function, through which the loop size will change,
then the first time I give the right result, and the next run I will give completely false results.

If you think this mistake falls within the kata to prevent then perhaps you could add this testcase to the tests?

It was a nice introduction to genetic algorithms.

I had to tweak my population size and iterations to get a successful run.
I wonder if my OO approach is readable and how I could improve it still.

match with (dutch) phone numbers

As I mention in the description, this is how it is dialed from/to holland
So yes it does depend on the country, should I make that even more obvious?
Or should I just remove those additional texts behind the example numbers that should be recognized?

Think I'll update the description to reflect this additional bit of information.
updated the description to mention that information.