Test coverage

To help find untested configurations, it would be helpful to have test coverage reports.

This could be a simple synthetic value to start (number of tested routing entries vs total number of routing entries). And possibly be extended to provide 'code coverage' reports indicating which lines of a configuration file are covered by the tests. Using one of the well established formats for the 'code coverage' reports might be useful when integrating the coverage reports with external tools.

@x-way Hi, I would like to work on this task. Thank you!