Writing Efficient Tests

Unit testing can be a blessing and curse at the same time. Once you start doing it on a regular basis, it can become an addiction. You test everything, you feel the satisfaction of 110% test coverage giving you confidence in your code. But after a while, testing suddenly seems to slow you down. Everytime you make a change in your code you have to adapt several unrelated tests. Adding a <ul>-tag to your template becomes a matter of minutes, rather than seconds. And, worst of all, your test suite is slow...

source: http://webmozarts.com/2010/03/11/writing-efficient-tests/
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