Hi, I added some notes on the blueprint: https://blueprints.launchpad.net/nova/+spec/remove-mox-pike I have seen quite a few patches trying to remove the use of "self.stub_out". While possibly interesting in the future, I think this should be out of scope for the mox removal blueprint. The aim of that method is to help us easily stop calling the mox related "self.stubs.Set" in a way that is really easy to review (and hard to get wrong). I think the current focus should be on emptying this list. I know we have had quite a few patches up around related tests already: https://github.com/openstack/nova/blob/master/tests-py3.txt Just wanting to double check we are all agreed on the direction there. Thanks, johnthetubaguy