Sample application I used for the examples in my conference talk at 360AnDev in Denver. It uses Dagger 2 to inject dependencies in production and uses a Fake store object in the integration tests.
What makes Android apps testable
Test Driving away Coupling in Activities
Testing MVP using Espresso and Mockito
Model-View-Presenter: Android guidelines
Android Architecture Patterns: Model-View-Presenter
Effective Android Architecture