How many times did you find yourself in an argument about whether or not a certain detail in some programming language or framework was implemented in a certain way? I’m talking about questions like these ones: Can a JS promise be rejected after resolution?
We used PhantomJS for automated UI testing for some time. It successfully helped us to be sure that our Polymer-component based pages behaved correctly. At least that’s what we thought. We used Mocha for testing with mocha-phantomjs package. Our tests looked pretty much the same: we created some components, triggered events and evaluated the results.