How to mock WebdriverIO.Element with sinon-chai

I’m creating a web testing framework wrapping wdio.js.

In my framework, I need to translate from my wrapper object to WebdriverIO.Element so that I can call getAttribute() which hangs off of $. But I can’t figure out how to spy/stub/mock $ or WebdriverIO.Element such that I can find out what parameter getAtribute() was called with.

Any thoughts?