How to test / debug GNOME Shell extensions? Is there any tool for that?

I would like to develop GNOME Shell extensions and found it's really easy to step into the development process but I still can't figure out how to debug / test my extensions effectively.

Are there any tools for that purpose? Is there any kind of real time console like we have on modern browsers or javascript servers environments?

Solution 1:

Yes, the real-time console is called "Looking Glass" and can be started by pressing Alt+F2 and typing lg at the prompt.

More info: https://live.gnome.org/GnomeShell/LookingGlass

Solution 2:

On Fedora 20 (and probably any new linux distro) you can use that command:

journalctl /usr/bin/gnome-session -f -o cat

It constantly (-f) prints errors generated by gnome-session in terminal window. I prefer -o cat flag as it shows full messages without timestaps.

On Fedora 22, I believe, it was replaced with:

journalctl /usr/bin/gnome-shell -f -o cat