We hope you weren’t planning on playing any of the World of Warcraft: Legion alpha during your own holiday break (assuming you have one). Blizzard has announced today that the alpha test will be going on break on December 21st, to return sometime early next year. There’s no discussion of whether or not the testing pool will be expanding as well.
World of Warcraft: Legion was announced at Gamescom this year, with a promise of beta later this year; it was later stated that beta would begin in the weeks following BlizzCon. It is worth noting at this point that Blizzard has been very careful to call this build an alpha through its testing.