I apologize if this information is published elsewhere, but because of the complexity of the web browser world and magento, I thought people might appreciate information on automated testing tools (free ones). Feel free to contribute your favorites to this thread or comment on the ones I have listed below.
Anyway for almost every site I build I use the following tools:
To check site speed and broken links on site entry:
==> http://tools.pingdom.com/fpt/ (I use this one most often)
To verify a site works in many browsers:
For a host of misc. tests:
Happy site development!