=== JUnit4 tests ===
(Note mcomella 5/5/16: they don't all pass for me locally. see [https://bugzilla.mozilla.org/show_bug.cgi?id=1271000 bug 1271000])
* Runs on [http://robolectric.org/ Robolectric], which mocks various Android libraries so you can write unit tests for Android libraries that would ordinarily have to be run on device