Best way to test a social ios app

What way would you recommend to test and ios app that has a lot of device specific communication with it’s backend?

At the moment I am developing my first ever app. For this I have made a backend using the google app engine with endpoints that takes care off all the interactions between devices. These interactions are however based on device specific information such as it’s UUID and and it’s location.

So far I have used the google endpoints explorer to fully test my backend. Than started developing the Ionic frontend and debugging it on my browser and phone (through the phonegap app) using ionic serve. Now I have reached the state where also the cordova plugins have to be tested for which I have borrow a mac to test the app in the ios emulator. I will however in the end need to test the complete app and how the interaction between different devices is handled. It is for that step that my question was posed.

Is there a way to do this without already having to submit the app to the app store? Any advice is most welcome and am also interested how your different development cycles look for a Ionic app.