There should be a mod which you can player dummies that arn't actually a player but to test it. Just like a smash bros dummy. You can adjust the dummy by putting it either to walk, have inf hp, jumping, and punches! You can also hit and use mods that are needed for two plays like the grab player mod to test them out! They also appear in the profile button which u see what players are there. It fully as the player code, just no player but just a test dummy! You can also change its character aswell (optional)