The way that zone.js works is by shimming out all standard browser/node APIs. That's a neat idea and seems to work quite well. It occurs to me that if its possible to provide your own custom shims then you could use that as a very flexible mocking system for tests rather than having to do stuff like rely on Sinon's fakeTimers.
Is doing this currently possible with zone?
Yes, you can, and
Sinon'sfakeTimersare beingpatchedin a PR ofzone.js(not released yet), but of course, you can create your ownpatchwith currentzone.js API.