Mock Battles

There are so many possible base designs and army compositions out there. Wouldn't it be nice to be able to test those out before putting your hard earned resources on the line? I propose mock battles, where a player can take bases of their own design and use a demonstration army to attack them. This would help players discover weak spots in their base design before it's too late. They would also have the chance to practice strategies with different army compositions. This could really bring the game to a new level.

Friendly challenges are already there. Anything else can be exploited.