Marco Trevisan authored Feb 07, 2020 and Bastien Nocera committed Mar 17, 2020

When creating a new unit we used to get the system bus via Gio.bus_get_sync,
however this has a singleton implementation, and so would always return the
same connection, creating issues in tests when a new test suite is added
because the newly got connection would be already closed.

So, just manually create a new bus connection, also close the bus and
cleanup the test bus in dbus.