Catch2 vs doctest

Look into doctest (https://github.com/onqtam/doctest). We use it in CESNET and for us it can be probably a drop-in replacement for Catch2 (similar or even same syntax) which compiles much faster.

Look into catch3 before migrating https://github.com/catchorg/Catch2/releases

added D-tests label

mentioned in issue #201 (closed)

I do not thing there would be much of an added value now.

closed