tests: Add ability to test different expected outputs based on Python version. Similar to the previous change, there was also a change in what gets escaped by `urllib.parse.quote` (as in: the tilde sign ('~') stopped being escaped). So now we need to be able to test different outputs in the tests, yay again.

[pytest]
norecursedirs = .* _darcs CVS .svn .git .hg *.egg-info dist build bower_components node_modules venv tmp* _cache {args}