Run tests on Android

Currently all of our tests run against the openjdk module. We should investigate running them all for Android as well (using emulators).

Some helpful links:
[Getting Started with Testing](https://developer.android.com/training/testing/start/index.html)
[Testing Your App](https://developer.android.com/studio/test/index.html)
[Building Instrumented Unit Tests](https://developer.android.com/training/testing/unit-testing/instrumented-unit-tests.html)
[Samples](https://developer.android.com/training/testing/samples.html)