Disclaimer: Blizzard has not publicly stated anything about this test realm.

A Wild Hearthstone Test Realm Has Appeared

Part of our day involves watching what Blizzard is up to with their games and we've discovered a push to the Battle.net client this evening which contains encrypted data for a Hearthstone Test Client. This could indicate a couple of things.

Hearthstone could be getting a Public Test Realm.

They are currently just testing out the new expansion.

Public Test Realms

If you weren't aware, Blizzard makes use of Public Test Realms (PTR) in all of their other game titles. This lets players test out upcoming game content before it comes to the live servers so they can help the team track down bugs and make sure the end product that is pushed out is awesome.

Ben Brode recently has gone on the record and stated that a PTR isn't just a positive, but also has downsides.

Quote from Ben Brode There are real downsides to a PTR. Because we ship on so many platforms, it would take at least a month of cards being fully spoiled before they release.

Not Just Expansions

Keep in mind that a Public Test Realm may not necessarily include upcoming expansions. One could also be used for:

Testing bug patches before they go live.

Making systems tweaks.

Card Balance.

Seeing how the recent patch introduced a lot of bugs to the game, it wouldn't be surprising to see the Hearthstone team taking future game patches more seriously and giving them a round of quality assurance with the community's help!