Two things here:
1) This means the test may only run as root, not user.  Running as a user will change the default networking to user-mode.  Since that happens automatically, it would be proper to flag this test as "root only" (I think that's the config param name too).
2) On my system (which I believe is mostly "default") it would get ``interface.source == {'bridge':"virbr0"}``.  I'm not sure where ``{'network':"test"}`` came from, or maybe I am missing something (or my system isn't setup right).