According to I1a9b6ed53 Buck's test runner doesn't skip abstract classes, but will if they are annotated as @Ignore. This may not be true any more; Buck seems to be marking the classes as NOTESTS. Mark them as @Ignore anyway, even if it's only as documentation. Also make classes abstract. Change-Id: Ifc8deef60037bbf0b446542498ba9055037bf5d9