Unit and integration testing an Android app that involves multiple users interacting with app in real-time

I've been gleaming the Android documentation out there on testing but I was just wondering how one would go about testing features in Android involving the interaction of multiple users such as in a chat application or a posting forum.

I would assume for unit testing a fair bit of mocking and stubbing would be used, and I've been thinking for integration testing I would have to launch multiple emulators to simulate how actual users would be using the application. The multiple emulators method seems like a plausible solution but fairly slow and somewhat of a hindrance to the development lifecycle. Also does anyone have experience testing applications with websockets where data comes in real-time?

Perhaps my mindset towards testing an application like this may be wrong, but if anyone could provide some advice or guidance on how to go about doing this that'd be great.