When people talk about open source they often talk about the products, not the process. That’s not really a bad thing (it is after all about the product), but it overlooks some really interesting things sometimes. For example open source tools used in open development.
A few months ago Jesse Ruderman introduced jsfunfuzz, which is a tool for fuzz testing the js engine in Firefox. It turned up 280 bugs (many already fixed). Because the tool itself is not horded behind a firewall it’s also helped identify several Safari and Opera bugs. It’s a pretty cool way to find some bugs.
Another test that many are familiar with is Acid 2 which essentially is checking CSS support among browsers. Ironically this one too was released when Gecko is somewhat late in the development cycle.
Efforts like this really help web development by allowing browser developers to have a baseline to compare their strengths and weaknesses. Having a little healthy competition as motivation can be pretty helpful too 😉 .