ArenaNet plans to offer a public beta test next week for the new PvP mode coming to Guild Wars 2: Heart of Thorns, saying this will be available to all Guild Wars 2 players in Europe and North America. This older article has details on their PvP plans, and here's word on testing:

The Stronghold public beta will start Tuesday, June 2 at 9 pm CEST (8pm BST) and ends on Wednesday, June 3 at 9 pm CEST (8pm BST). Stronghold mode is an exciting new competitive mode coming to Guild Wars 2: Heart of Thorns that blends deep strategy, role-based play, and immersive story elements into PvP. Like previous Guild Wars 2: Heart of Thorns beta events, players are free to capture video, screenshots and even livestream their performance in Stronghold mode so even non-Guild Wars 2 players can witness the in-game fun.