Since each pytest module starts httpd and stops it again, the config files can be very local to the tests being done. That makes them quite easy to understand and startup times very short.
Sadly, that's an enormous regression from the perl-framework. You'll note that our suite can be started in server mode on a significantly limited test host environment, and the tests applied from a more comprehensive test client instance. This proved especially helpful on aix, hpux and other odd ball architectures when they were part of my focus.