testing a system app

[Nicolò Parolini]

I am currently developing an app which must run as system. We got our own Android image, fully rooted, and we either preinstall the app at production or we can install it by copying into /system/priv-app and letting Android install it at boot. So I can get it signed with whatever signature I want. I am trying to test it with Selenium (Java), how can I get Selendroid to actually start it as system or hook into it without installing it again? The app must run as system as its main functionalities depend on it, so it is not an option to test it as a user app.

Thank you