Unit Tests include sets of one or more programs which are designed to verify an atomic unit of source code, such as a method or a class.
Android platform comes pre-integrated JUnit 3.0 framework. It's open source framework for automating unit testing. Android Testing Framework is powerful tool for developer to write the effective unit test program.
An addition to Unit testing is User Interface (UI) tests. These tests relate to UI components of your target application. UI tests ensure that your application return the correct UI output in response to sequence of user actions on device.
The common way to performance UI tests on device is Android Instrumentation. But this has performance issues. One of the best tools to conduct UI testing on Android is Robotium .