Inching slowly (but methodically) towards my first implementation of In-app Billing, I reached the point in which I can actually run the market billing sample application: The app is signed and uploaded to the AM, the "product list" has been created per the instructions and a test account has been set in both Google and the phone.
But when I proceed (successfully) with a purchase, despite selecting the test account on the AM, I am prompted to confirm the purchase with my real gmail account, to which my real credit card is linked.
When testing PayPal, for example, one can create test accounts, too, with fake CC numbers, to test freely w/o burdening the real CC system.
Is this available (or possible) for In-app Billing development & testing, too?
Update: I tested this on a different device, having only the test account set, and sure enough the Android Market behaves erroneously, responding the following error message:
The item you were attempting to purchase could not be found.
I know that the item is there and that it is set up properly in the Android Market because this error is never issued on the device with the real account with the CC number (there I receive a perfect behavior with the masked CC number, the Total and an Accept & buy button). Why does Google write such misleading error messages?
Update: I found this incredible thread, which seems to partially answer my question. Unless something new has been introduced by Google since then.
You have to use a real credit card. However, you can always refund your test purchases!
Note that you'll have to make the purchases from a test account that's separate from your developer account, since Google Checkout doesn't allow an account to buy from itself.
Test accounts are useful when you upload your application as a draft application,not published.Then using test account you can do even purchase of unpublished application.Hope this helps.
来源：https://stackoverflow.com/questions/8760512/do-test-accounts-require-real-credit-card-to-purchase-via-in-app-billing