Instructions to test xfce4-notifyd may fail

[pierre]

In the book, we say to issue:

notify-send -i info Information "Hello $USER, this is a test"

to test xfce4-notifyd after installing it. But there are several reasons why this may fail:

• DISPLAY is not defined in the systemd user environment. Then, since xfce4-notifyd is started by systemd, it cannot find the display and fails
• several .service files with the same bus name "org.freedesktop.Notifications" may be installed in /usr/share/dbus-1/services, and the wrong one may be used. An ​old thread seems to conclude that the only way to avoid this is to remove the faulty file(s).

We should therefore decide how to modify the instructions so that the test does not fail in the above cases. We can either:

• tell the user to run:

     systemctl --user set-environment DISPLAY=$DISPLAY
  

  and to ensure that only one .service file containing Name=org.freedesktop.Notifications is in the services directory
• start the daemon before running the test:

     /usr/lib/xfce4/notifyd/xfce4-notifyd &
  

• remove the test altogether (we don't test other notify daemons in this way)

But we cannot leave the instructions as they are...

[Bruce Dubbs]

I like the idea of using '/usr/lib/xfce4/notifyd/xfce4-notifyd &'. If there is a conflict it returns 'Another notification daemon is running, exiting'. For testing that doesn't seem to hurt anything.

[pierre]

Done at faf040c2