The latest test realm patch notes can always be found at:
http://www.wow-europe.com/en/info/underdev/testrealm.html

The latest patch notes can always be found at:
http://www.wow-europe.com/en/patchnotes/

General
New art textures have been added for Argent Tournament mounts. Any mounts already purchased from the Argent Tournament vendors will be updated automatically. Argent Tournament mounts with the old textures will still be available for purchase from the Argent Tournament vendors for a small Champion’s Seal and gold cost (standard faction requirements apply).
Copied Test Realm characters will no longer be copied with their achievement history in order to better facilitate the character copy process.

PVP
Vehicle health and damage output in Strand of the Ancients and Lake Wintergrasp now scale with the item level of the operator’s gear. Power scaling is now 1% damage and 1% health per average item level.