Notice that the tests you write using httpUnit are more like system tests - you need to deploy the servlets to the servlet container before running the tests etc.
You can also test servlets by calling the doXxx method(s) directly and providing a dummy/mock-implementation for the response, request and accompanied objects. You can download a simple implementation from
http://www.dpunkt.de/utmj/utmj-servlet.zip Another one can be found at
http://www.mockobjects.com/
The soul is dyed the color of its thoughts. Think only on those things that are in line with your principles and can bear the light of day. The content of your character is your choice. Day by day, what you do is who you become. Your integrity is your destiny - it is the light that guides your way. - Heraclitus