Unit testing on the device

During the final review of the book, the master branch (the totally unreleased versions) of the nativescript command introduced the brand new nativescript test command. Fortunately, I saw something appear in the repos and asked about it. Yours truly, living totally dangerously, pulled the absolute latest and greatest master versions of everything so that I can document the all new bleeding-edge way to do unit testing on devices and emulators.

The latest and greatest daily master runtimes are automatically built for all platforms on http://nativescript.rocks as a community service. So, in all reality, it was a simple download and install, and then I was running the latest and greatest bleeding-edge NativeScript code. Typically, the only reason you run from master is if you need a fix or some feature that isn't going to show up until the next major release, which might be a while from now.

Until now, we were trying to test our code outside of NativeScript. This is...