The following screed was originally published at gist.github.com/54177 but has been copied here for posterity and because people keep asking me on IRC for the original link (it must be hard to find on gist for some reason).
John Barnette with a must read piece for anyone that’s ever written a Rakefile.
James Carr’s classification system for unit test smells and anti-patterns. This is almost three years old but still extremely relevant judging by the test suites I’m working with today. I’m guilty of more than a few of these. Via @coda.