Ubisoft has confirmed the date of the For Honor Closed Alpha, with the test set to take place from September 15th until September 18th on PS4, Xbox One, and PC. To apply for access you can go to the official site and register your interest along with the platform of choice. Alongside this announcement a new trailer has been released which gives a bit more depth about the Samurai, Viking, and Knight factions.
For Honor will be available on February 14th 2017.
Source: Press Release