example object get passed into `fn`

I've set up a repo to reproduce this issue: 

https://github.com/aars/machinepack-test-issue#test-machinepack-mocha-oddity

As it says, the actual object defined in `using` is not passed into `fn`, instead the first level of the `example` object is. I've tried not using such a generic name as `object` to no avail.
