I went to BarCamp Manchester (UK) yesterday (we also sponsored the after party) and did a talk on testing which I've published on Slide Share:
Overview: you should test your code and require tests on code you are modifying, otherwise you can't be sure what effect your modifications have had and have no idea if you've introduced a regression or new bugs. There was a discussion at the end about while this being a great philosophy, it's not easy to stick to.
Links to various resources for those interested in follow ups. Wikipedia offers good descriptions and overviews of the terminology used and explained during the talk (the slides unfortunately don't speak).
- http://en.wikipedia.org/wiki/Unit_test
- http://en.wikipedia.org/wiki/Integration_testing
- http://en.wikipedia.org/wiki/Acceptance_testing
- http://en.wikipedia.org/wiki/Test-driven_development
Software I mentioned during the talk is:
- http://cruisecontrol.sourceforge.net/
- http://emma.sourceforge.net/
- http://cobertura.sourceforge.net/
- http://www.atlassian.com/software/bamboo/ (commercial)
- http://www.atlassian.com/software/crucible/ (commercial)
- http://www.atlassian.com/software/clover/ (commercial)
I'm not suggesting you need to buy software, I'm suggesting you need to use software (free or otherwise) to give yourself a test platform and therefore confidence in your code.
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