The Environmental Vandal
A 'unit' test which for various 'requirements' starts spilling out into its environment, using and setting environment variables / ports. Running two of these tests simultaneously will cause 'unavailable port' exceptions etc.
These tests will be intermittent, and leave developers saying things like 'just run it again'.
One solution Ive seen is to randomly select a port number to use. This reduces the possibility of a conflict, but clearly doesnt solve the problem. So if you can, always mock the code so that it doesn't actually allocate the unsharable resource.
