Automation Testing for Chat Based Application or Push Notification

I Wonder if is there any possibility of testing the Mobile Chat based application through automation scripts. Lets say we have whatsapp, FB, Skype chat based apps. How people will be doing testing for these apps apart from manual?

I can automate on one side of mobile through some automation tools selendroid, see test and some other like open application, search a contact ,and send text message. But how on the other side of mobile will be automated ? like as soon as it receives message it replies with same message.

Even how push notification automation testing is done? I can see some apps which do auto reply for sms , but thats not works for testing.

Kindly suggest your thoughts on this.