Run unit tests on Save with Android Studio

Has anyone managed to make a reasonably comfortable setup for their project where unit tests run on every save?

I currently have a split project -- An Android Application project, and a Java project that the android application depends upon. I write unit tests for the Java project and run them manually every now and then.

In my understanding, to make this happen as expected, I also want to have incremental builds for the Java project. I am not sure that this is feasibly possible while using Gradle with its current state of affairs.