Ruby on Rails Debugging Tools

Scott Raymond's "Ajax on Rails" book contains a chapter on debugging and testing Rails applications. Unfortunately, a lot of this content is not applicable to Rails 2, as script/breakpointer has been removed from the framework and replaced by ruby-debug.

Fear not. Railscasts has an excellent screencast on ruby-debug, covering installation and basic usage of the tool. Data Noise explains some more advanced uses, such as remote debugging, here.

Another tool described in Ajax on Rails is Rick Olson's Routing Navigator plugin, which was also doesn't seem to work with Rails 2.