Testers must be registered as a License Tester in the seller's Seller Portal profile. If you do not do this you will experience issues when testing your implementation.
Samsung In-App Purchase uses "operation modes" to test your application in various states.
The operation mode is set through the Billing Service:
The type of responses from the store is determined by the state of the application and the operation mode as per the table below:
|IAP Test||Transactions||IAP Operating Mode||App Status|
|Always Successful Side Load||No charge||Registering|
|Always Fail Side Load||No charge||Registering|
|Production Closed Beta||No charge or Charge (depends on type of tester)||Beta Deployed|
Do not test when the IAP operating mode is
OPERATION_MODE_PRODUCTION and the app status is Registering.
IAP functionality is not supported under these conditions.
For more information on these modes and the transaction charges for different user types, see the guide here.