How to test an Android Library Project

Quoting the documentation:

"There are two recommended ways of setting up testing on code and resources in a library project:

• You can set up a test project that instruments an application project that depends on the library project. You can then add tests to the project for library-specific features.

• You can set up a standard application project that depends on the library and put the instrumentation in that project. This lets you create a self-contained project that contains both the tests/instrumentations and the code to test."

In your test project simply change the package name so that it's the same as your library's package.For example, you have a library whose package is "com.example.lib". Create a test project targeting your library. In the manifest file you'll see package="com.example.lib.test", and targetPackage="com.example.lib". Just change the package from "com.example.lib.test" to "com.example.lib" (targetPackage leave as is).

Also, make sure that the library is referenced to your test project NOT in Java build path, but as a usual Android library : in Eclipse it must be shown as library in Project->Properties->Android tab, but not in Project->Properties->Java Build Path tab.

Then run you tests.

Per the documentation:

Testing a library module is the same as testing an app.The main difference is that the library and its dependencies are automatically included as dependencies of the test APK. This means that the test APK includes not only its own code, but also the library's AAR and all its dependencies. Because there is no separate "app under test," the androidTest task installs (and uninstalls) only the test APK.When merging multiple manifest files, Gradle follows the default priority order and merges the library's manifest into the test APK's main manifest.