Есть ещё такой способ теста:
Testing with static responses
We recommend that you first test your In-app Billing implementation using
static responses from Google Play. This enables you to verify that your
application is handling the primary Google Play responses correctly and that
your application is able to verify signatures correctly.
....
You do not need to list the reserved products in your application's product
list. Google Play already knows about the reserved product IDs. Also, you do
not need to upload your application to the Developer Console to perform
static response tests with the reserved product IDs. You can simply install
your application on a device, log into the device, and make billing requests
using the reserved product IDs.
"Also, you do not need to upload your application to the Developer Console" -
в зависимости от нужд это может сгодиться.