A big cost area in testing is manual tests of the user interface. Therefore, a wide range of tools have been developed to automate running tests at the HTTP level. Selenium is a popular tool implemented in Java, for example. In the Node.js world, we have a few interesting choices. The chai-http plugin to Chai would let us interact at the HTTP level with the Notes application, while staying within the now-familiar Chai environment. ZombieJS is a popular tool that implements a simulated browser which we can direct to visit web pages and perform simulated clicks on simulated buttons, verifying application behavior by inspecting the resulting behavior.
However, for this section, we'll use CasperJS (http://casperjs.org). This tool runs on top of PhantomJS, which is a headless version of Webkit. Webkit is a real browser engine that's at the heart of the Safari browser. PhantomJS encapsulates Webkit so it runs completely headless, meaning that there...