The tests are intended to be run using Nose.  
http://somethingaboutorange.com/mrl/projects/nose/

To run tests, simply install nose, and then, in the eventlet tree, do:
   $ nosetests

That's it!  Its output is the same as unittest's output.  It tends to emit a lot of tracebacks from various poorly-behaving tests, but they still (generally) pass.