I am in charge of testing an enterprise web application that makes heavy use of AJAX. I need to build a system that allows continuous running of tests without human interve
Take a look at LoadBooster. It is a cloud-based load testing service which utilizes headless browser PhantomJS to test web sites. Disclaimer: I work for LoadBooster.
You might be able to take advantage of some of the available JavaScript unit testing tools to assemble the sort of environment you need.
For example I've found that loading env.js in rhino gives an acceptable fake browser for testing most JavaScript. It falls short on certain DOM attributes, like elements sized relative to their window, but that hasn't been a serious problem in my experience.
See also:
Have a look at WebKitDriver. The project includes headless implementation of WebKit.
This has been done by the guys over at http://www.phantomjs.org/. In their own words:
PhantomJS is a headless WebKit with JavaScript API. It has fast and native support for various web standards: DOM handling, CSS selector, JSON, Canvas, and SVG.
PhantomJS is an optimal solution for headless testing of web-based applications, site scraping, pages capture, SVG renderer, PDF converter and many other use cases.
PhantomJS is created by Ariya Hidayat