This concise book walks you through how to get unit testing and test driven development done on Android, specifically using JUnit 4. You'll learn how to do agile development quickly and correctly, with a significant increase in development efficiency and a reduction in the number of defects. Up until now getting JUnit testing up and running in Android was not for the faint hearted. However, "now it's in Android Studio, there is no excuse," according to author Godfrey Nolan, president of RIIS LLC. Android developers are faced with their own set of problems such as tightly coupled code, fragmentation, and immature testing tools, all of which can be solved using existing agile tools and techniques that this short book will teach you.