Hey Austin Wood!
Definitely this article needs a LOT of updates. When I wrote it, Jest 15 was not there. Right now, by default everything comes unmocked. You can see a more recent example in my article of Jest Snapshots with Redux: https://blog.callstack.io/unit-testing-react-native-with-the-new-jest-ii-redux-snapshots-for-your-actions-and-reducers-8559f6f8050b#.rfvllupjs
I’ll definitely try to update this article when I got time.
About the second part of your answer, I did not try to test it with the `withExtraArgument` (I did not have to use it either). But I’ll try to take a look too. Thanks for your feedback :)