And under circumstances testing the own url parser _alone_ is only half (?) of the story. The other URL parsers within the system or in the line need to be test

And under circumstances testing the own url parser _alone_ is only half (?) of the story. The other URL parsers within the system or in the line need to be tested, too. Which mathematically might not be possible. So next to the URL parser it is likely practically to have an URL filter. And with it, a good test-suite, too. (I don't do any bets thought, sorry)