R1:1239cfdeaf3a

Add a bunch of tests for subclass implementations

Summary: Add a bunch of tests to ensure that subclasses behave.

Test Plan: `arc unit`

Reviewers: eadler, #blessed_reviewers, epriestley

Reviewed By: eadler, #blessed_reviewers, epriestley

Subscribers: epriestley, Korvin

Differential Revision: https://secure.phabricator.com/D13272