Can you use all of a gift card on purchase that is more than gift card balance (+ pay rest with credit card)

If I had a $25 apple gift card (and a credit card registered for apple purchases), applied it to my phone, and then made a $30 purchase in an app, would the gift card be used in full and then my credit card would be charged $5 or would my credit card be charged all $30 since there wasn't enough money for it on the gift card?