There is not a testing method that uses a dummy credit card to test without creating real orders. The method that we recommend for testing is to create a promotion code in the admin area of your site that will create a nearly 99% discount. When checking out, apply the promotion code to the order. This way very little will be charged to your credit card. To do this, go to Sites > [Site Name] > Promotions. Click the "+" next to "Add New Promotion" at the top left of the page. Then create a promotion code that takes 99% (or whatever percentage you would like) off of the subtotal. Set the usage to "Normal." You can then use the promotion code on all of your test orders.For more information on creating promotions please refer to the chapter Ch. 059 Promotions
Note: You will need to have some fee being charged for the test to work.