@bclwhitaker: @heff pointed me at the [vtt.js](https://github.com/mozilla/vtt.js) tests as a strategy to cut down on the boilerplate in our tests cases. I like the very declarative test case setup but really wanted tests to continue to run in real browsers instead of just node. This is my attempt to balance those two concerns. You can add any m3u8+json file pair, and they'll be automatically exposed to the test harness and compared for deep equality. I converted all of your test cases to this format. Let me know what you think.