Submitting App to the Play Store With In App Billing

Hello everyone,
I have developed an app on kodular and have tested the in app billing with the test product ID and the IAP calls correctly with the test payment.
My questions:
I am now wanting to send my app for review so how do I do this? So I am unable to create subxcription profiles for the app without uploading the app so do I get it reviewed first with the test product ID and then implement the subacription later?
Also do google pay have a api that can call my own webservers after transactions so that I can update my DB, just like paypals IPN?