Granting com.google.android.c2dm.permission.SEND permission (e.g. in Android tests)

[nieszkah]

It appears the ability to send push notifications from adb has been removed. 

A recommended option, up till recently had been to run as root and send broadcasts (e.g. https://medium.com/@raunaksett/debug-fcm-firebase-cloud-messaging-notifications-using-adb-298a071e0039 )

Running as root however is no longer possible (with a `adbd cannot run as root in production builds`) and though various people online recommend workarounds to that, they all seem in agreement this would not work in firebase test lab. 

Is anyone here aware of how the current restrictions could be bypassed to allow one to write UI tests for android applications that do not rely on external services?