Android and unit testing, the right way

I am very new to automated testing of java code. I am working on a realtime android app making use of google maps, a REST API primarily. For some reason I am not able to find some detailed resources for testing my classes.

During my research I came across tools like Mockito and Robotium alongside JUnit for mocking android objects but I want someone experienced to guide me towards right path to avoid wasted efforts. Thank you, any help is appreciated.