Goldfishing, or playing without an opponent, is a simple way to begin testing your deck. These very basic types of testing are a great way to identify basic problems with your deck so that they can be fixed before your first games with it. When trying out a new deck idea, it’s often a good idea to put your idea through a few basic tests before trying it out in the real world. Once you’re done looking over your deck, it’s time to start looking at testing it. If something pops out at you from the checklist, run through your deck again to make sure you’ve got what it needs.