I have recently found a great online battle simulator for Pokemon. You can test out your teams using a wide variety of Generations and Pokemon going all the way back to Pokemon Red/Blue/Green! You can also use special moves that certain Pokemon can only learn from events (e.g. Entei with Howl or Victini with Fusion Bolt). The link to the site in in my signature.
NOTE: I'm not sure if this is allowed so if it isn't, just delete this thread.