A fresh install of Ubuntu Server is refusing to boot and hanging on "Adding 524284k swap on /dev/mapper/test--vg-swap_1. Priority:-1 extents:1 across:524284k
I can get around this by dropping onto recovery mode and just resuming to a normal boot.
It is doing this because Ubuntu is trying to switch to a high resolution video mode for the console and your hardware isn't cooperating.
Fixing this while at the machine
When Grub2 shows up:
With any luck it will boot into the login screen. This won't save that option but at least now you can edit the file for Grub2 and update it to save that option if it works. I blogged about this recently.
Fixing this for good
How did you add it? You may want to format the swap again. What you can do is boot under rescue mode, mount the vgs and do:
Then add it again to the /etc/fstab if it's not present.