[bjackman]

Yes, I recently switched my org to using Zuul for this purpose; by having an internal speculative queue of future states for master you can have multiple pending changes tested at once, while also ensuring that the tested code is exactly what goes into master. So far it's been a really good experience, in particular as our tests take a long time.

It sounds like Uber's thing has a lot more smarts regardint deciding what gets tested. For the scale I work at (<200k lines of code) that isn't necessary.