Test Driven Development (TDD)

http://epf.eclipse.org/wikis/xp/xp/guidances/guidelines/test_driven_development_tdd_D7F1F440.html

http://java.dzone.com/articles/making-test-driven-development

http://www.vogella.com/articles/JUnit/article.html

http://code.google.com/p/econference4/wiki/HowToWriteJunitTestCases

http://www.jguru.com/faq/view.jsp?EID=25537

http://www.tutorialspoint.com/junit/junit_test_framework.htm