I've successfully created a keystore to sign system apps to be tested on android emulators. I can install the apk on a 6.0 image but got no luck on a 8.0 image. It fails with the message:
INSTALL_FAILED_SHARED_USER_INCOMPATIBLE Package xxx.yyy.zzz has no signatures that match those in shared user android.uid.system".
The keys that i used were the ones available on aosp-mirror github. Is there a way to sign an apk as a system app to be used on a 8.0 android emulator?
You should try to use an Emulator without Google API's or Google Play Services.