I've setup Firebase App Distribution on our projects with the provided "App Tester" android app which is amazing. Although I identified one major issue that I know a lot of people using this tool are experiencing and from what I saw, nobody actually knows the reason behind it.
The issue is : I download my app from the Play Store. Then I deploy a new version of my App on Firebase App Distribution to test it, go to App Tester, click on my app and click on install. I get the error "Installation failed" with no more details. To resolve the issue, I must uninstall the app from my phone and click install again to have a successful install.
The reason behind this is that Android does not allow a signed APK to be updated by another APK signed with a different key.
The APK that I download from the Play Store is signed by my CI but then it is signed again by the Play Store with their signing feature (can enable/disable it I know but I prefer to keep it enabled). The key used by Play Store to sign again my APK is private and nobody can access it.
But the APK that I upload on Firebase App Distribution with Fastlane is signed by my CI, not Play Store. So the key is different and that's why App Tester fails installing the app.
Can't I tell Firebase to do the same process of resigning my APK with the key used by the Play Store ? It is really annoying to uninstall my app whenever I previously installed it from the Play Store. More importantly, it's annoying for the testers at my company that don't understand why they get this error and don't know what to do...