tirsdag den 26. februar 2008

Full testing with JavaScript

In my efforts to achieve a full and robust test of web applications I have run into several difficulties.
1. simulating different browsers
2. keeping test scripts simple
3. fragile tests

Simulating different browser

Initially I achieved this using the Canoo Webtest. Though powerful, this integration fo different third party frameworks has shown not to be able to handle JavaScript very well. This means that if you have no control over the javascript in an application, the test becomes very fragile.

Instead I concluded that the best way to simulate the different browsers is not to actually simulate them. Instead it is very efficient to inject JavaScript along with your tests into the page that you wish to test and thereby testing on the executed page.

Several issues comes with this. Firstly, the security in the browser won't allow you to execute JS on another page, if they are not from the same domain, so you have to execute the test from the domain itself. For inhouse testing this is not a problem, but involves some more deployment.

keeping test script simple

This is really up to the implementation of the web application. If its based on poor standard, test script become increasingly difficult. If for example id's are duplicated or tags are broken, the traversal of the DOM becomes difficult. The best solution to this is to stick to strict xhtml and keep your styles in CSS while maintaining ids on all divs.

A second worry is that the script becomes complicated with lots of hacks and too much code, but this is really up to the framework being used. The better the framework and web application coexist, the easier and cleaner the scripts become.

fragile tests

With a low sense of 'standards' in a project, the test become very fragile. The team must agree upon how to use divs and lists etc. Once referring to an id of a div or anchor at a specific position, that has moved or is renamed, the script might have to be rewritten. The framework should help avoid too specific referenced. Whenever referencing an element in the DOM, reference it as lenient as possible.

here is an example of how the framework might be implemented

MyTestFramework.clickLink = function(text) {


I'll be working on this and post when I have a functioning framework. I'll proably pull in some JSUNit library and use that for a backbone for TestCase and TestRunner.