The best way to test your cart is to do a
purchase and then void the transaction on Authorize.net afterwards so
the charge does not carry through. Authorize.net will only process your
charges at a certain time each day; the same time each day.
After you put through your order and pay
for it, login to Authorize.net and then click 'Unsettled
Transactions'. Then, click on your payment and you will see a button to
void the transaction.