~ to open the console
research_technologies <--enter command to get real smart
~ to close console
Design your test ships like normal. I make my target ships have no weapons etc.
~ to open console
add_ship [shipname] # <--Insert the name of the ship you made, and how many you want. They'll pop out as a fleet (no brackets)
add_ship [othershipname] # <-- Get your other test ship(s) out
attackallfleets
~ to close console
Unpause. FIGHT!
attackallfleets again will stop them fighting so you can disband them etc.