Testing JavaScript code (and releasing realStorage 1.2)

The motivation behind the blog post is the release of realStorage 1.2. Two main things have been introduced in this version. One is helper functions which handle the (un)serialization of JSON objects into localStorage. This was the last idiom I have personally come across in my thesis work and thus ends (for now) my desire to add convenience functions to realStorage. After this I probably have the greatest desire to get a Gears back-end going for those browsers that do not support localStorage. But that will have to wait until Chromium on OS X begins to support the plug-in.

The other thing I added to this release was support for running the tests using JsTestDriver. This has stemmed from me trying to figure out how to do reasonable testing of both web applications and JavaScript libraries for my thesis work.

For JavaScript libraries I have been using QUnit, the testing framework for jQuery. It's worked out rather well. It is simple and has the proper concept of "sameness" for JS objects (if you have ever tried to do ``{a:42} === {a:42}`` you know what I mean). It also has XHR test support which is handy. Plus the jQuery code uses it so I can delve into their code to find example usage. And finally it has a nice HTML output page to look at failures. Tie that into the developer tools that come with WebKit browsers (e.g. Chrome and Safari) and my debugging situation is pretty good. I personally don't use Firebug as I have found it to be buggy too often and I like the WebKit developer tools. The only thing Firefox has going for it the Work Offline menu option which is handy when you are developing offline web apps.

But having an HTML page for testing a browser is a bit tiresome when you want to test against multiple browsers, which is where JsTestDriver comes in. It's a jar file that lets you "capture" multiple browsers to a server which then runs your tests on all of the captured browsers. Designed for continual integration testing, I find it handy to quickly test all of my tests on multiple browsers while I am developing. Plus there is a QUnit adapter in their svn repository which lets me code in QUnit while running it simultaneously in multiple browsers when I am not actively debugging.

For testing the view of a web app I have found WebDriver works well. There you write Java code (icky I know, but you can use other JVM languages) which uses the Selenium Java bindings and launches browsers to test them. What's neat is that it simulates key input and mouse clicking, so if you use Firefox for the testing browser you can watch the test enter text as it runs (albeit rather quickly).

So that's my JavaScript testing toolchain that I have come up with. So far it has worked out well and helped to keep me sane when dealing with JS.