I want to test the state of my app when it's left in the backstack for too long.
When I open like 20 apps one after the other my last used app (which is the app I'm testing) eventually terminates and a savedInstanceState occurs. Is there a way to simulate this behaviour for the app I'm testing without having to open another 20 apps in order to burry my app in backstack?
Yes, there's a simple way to do it. Just enable Do not keep activities under Developer options. Your activity will then be immediately destroyed as soon you leave it and onRestoreInstanceState() will be invoked when you return.
Alternatively, you can force a configuration change (like orientation) and that will recreate your activity too. One issue with this approach is that there's a bug with some JellyBean/KitKat versions where the emulators fail to rotate. (This works fine on a device though.)
The workaround is to install the RotateScreenOrientation.apk which can force the emulator to be in portrait or landscape but this quickly becomes tedious if you have the option to Wipe user data on emulator start enabled.