Wondering this as well.. It has been offline for quite a few days and really want to test out some cannons soon.
Cannon test is back up as far as I know. PM me or leave a message on my wall if you have any inquiries. ~Jince222
It was turned to a lobby ;-; u do /server cannontest you get kicked to a lobby, you do it again there it says you are already connected to cannontest, you connect to a diffirent /server lobby(number) then do /server cannon test it kicks you back to the same first lobby.
Pretty sure its 1.7, still going to test it though Nope, its just down. http://guildcraft.org/threads/cannon-test-server-released.12243/
I believe it used to work as 1.8 previously, unsure of whether or not the server will or will not be back up, waiting does no harm for me I guess.
I know this is kinda off-topic but OMG BLUEJAY IS ONE STEP FORWARD TO BE A PRESIDENT(admin )YOU ARE A MOD NOW congratz man