Blizzard launches test server where you will be able to be a part to test new PvP features. Every Friday from February 3rd you can join this server to check all features comming with v7.2 which was called PvP Brawls. In this mode you'll be able to fight with models from other Blizzard titles such as HotS, Hearthstone etc. Play fast with normal PvP rules on standart-sized arena, play 15v15 or with additional options like no gravity in Eye of the Storm.
All Blizzard employees will be marked with special tags so you can easily gank them!
Read more info on WoW community forum