In North Boulevard of Lumiose City is a building known as the Battle Institute. This buildin, will allow you to test your teams out against a variety of trainers. There are two modes for you to test your teams in; Single Battle and Double Battle.
The Battle Institute has the standard Pokémon restrictions that exist online with Flat Rules and in the Battle Maison meaning Pokémon such as Mewtwo and Xerneas will not be able to be used.
The task here is to select your team, 3 Pokémon in Single Battles and 4 Pokémon in Double Battles. You will face up against 5 consecutive trainers and will move on to the next battle regardless of if you win or lose the battle. Each team gets progressively more difficult to defeat and start using stronger and more in-depth strategies in order to provide even more of a challenge.
There is also a download option which will allow for the download of special training scenarios through the Nintendo Network, and locally, but it is unknown whether or not this shall be utilised as a feature.