14c8f5f94c
The mutter tests require to run in a valid environment where a display is available and a session bus, however currently we rely on the current environment, and this may lead to unexpected behaviors. So let's just ensure that a display is running through xvfb-run and that a session bus is running in a temporary directory. We also ensure to use the gsettings memory backend, even because by setting TestEnvironment we ensure that no other env variable is leaked to the test. Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1876>