The World of Warcraft Classic site has been updated with the news that closed beta testing will be ending on July 12th. The team has plans to take on verified bugs out of the 17,000 reports made over the last seven weeks of testing. This will, according to the post, make "Classic a better experience for everyone when it launches on August 27th".
The final stress test prior to launch will take place on July 25th and July 26th and it will be a global event. The plan is to thoroughly test multi-region hardware and it will be a chance to "test the fixes and tweaks that have been made and are making to the game".
Read more on the World of Warcraft Classic forum.