Defense Tester

This might have been brought up already, but what about the idea of being able to test your defense against others in your clan. Maybe be able to choose ghost troops for free, but only ones that you can already train for a regular attack, and be able to attack someone in your clan to test their defense and your attack strategies. This way players can keep active while waiting for long upgrades and it won't cost you any resources to train troops as they are only "ghost" troops and attacking doesn't actually cause any damage or loss of resources to your clan buddy. After the attack, you can leave them a message with advice on where to improve or something like that...

Thanks,
-Rich