I think that we had plans to use Fedora Messaging back when it was first proposed but I don't think that we've talked about it recently.
The current timeline predicts that fedmsg will be deployed into production by the end of the calendar year, potentially sooner. From what I can gather, there is an expectation that AutoQA will eventually use fedmsg to broadcast results and schedule tests, replacing the current method of direct Bodhi comments and cron jobs to poll Bodhi/Koji.
I don't think that it's anything we have to worry about right now but it's probably something that we want to start thinking about in the near future. Hopefully there will be some test support code coming with fedmsg (mocks/stubs, mostly) that would help us in development but AFAIK, none of that has been written yet.
I'm planning to keep attending the Messaging meetings and will pass on updates as I learn about them.
Tim