GWT testing best practices
http://www.youtube.com/watch?v=T_CLzgEL7FA
http://code.google.com/p/gwt-test-utils/
http://blog.jteam.nl/2008/03/09/test-driven-development-for-gwt-ui-code/
http://blog.danielwellman.com/2008/11/test-first-gwt-article-in-november-2008-better-software-magazine.html