I am working on an Android 4+ app that is free and includes some In-App Purchase items. Some testers are participating in the current beta-test and once the final version is published I would like to let these testers use the IAP items for free.
Is there some "easy" or official way to do this?
This will be my first app in the Play Store (only worked for iOS so far) and I do not know if there is any possibility to create promo codes or something like this to let users purchase non-free IAP items for free.
The only solution I found so far would be some kind of back door within the app, e.g. "Go to page XY, click twice on image A to bring up the unlock screen, enter your username and key..."
Of course this would work but I do not like this solution. Beside the additional work to implement such a solution it would not be really save. I do not know most of my testers in person and if one decides to publish his unlock key on the internet I cannot prevent all kind users from unlocking the app for free (at least not in the current version).
So, is there any way within the Play Store API to get this working?
Short answer: No!
Detailed answer and a possible way to do this:
Right in the Developer Console --> Settings --> License Testing Panel. There you can add up to 400 eMail adresses. Anyone who's using one of those eMail adresses is able to make test-purchases, this means they won't be charged but the Google Server will respond with something like "Yeah he/she bought this item".
Limitation: It's meant test purchases, mainly for applications that aren't published.
You can use any Google account as a test account. Test accounts are useful if you want to let multiple people test In-app Billing on applications without giving them access to your publisher account's sign-in credentials. If you want to own and control the test accounts, you can create the accounts yourself and distribute the credentials to your developers or testers.
Though it's still possible to make test-purchases in published application. But there's one major drawback: The purchase will be cancelled automatically after 14 days.
Test purchases are real orders and Google Play processes them in the same way as other orders. When purchases are complete, Google Play prevents the orders from going to financial processing, ensuring that there are no actual charges to user accounts, and automatically canceling the completed orders after 14 days.
To sum it up: The In-App Billing API doesn't offer an official way to do something like this. If you wanna do this you have to implement your own solution.
See also this SO-Post "Coupons for In-App Billing" which discusses this topic as well.