Appstore approval process for app using third party authentication service

I have a mobile application for iOS.

The application uses a third-party application to power the login to the application (eg: Google Authenticator). The application is targeting a specific community and assumes all the users already have access to the third-party app. Login to the application happens smoothly as they already have the third-party app installed on their phone.

Now when I submit this app for approval to Appstore, I am not clear on how I can provide test access to Apple. As the app will be on the production setup, there are no test accounts that can be provided here.

If anyone in the community has prior experience here, kindly shed some light