SharpDevelop 4 has been updated to support running IronPython
unit tests that use the
unittest2
library, as shown in the screenshot below.

Make sure unittest2 is on the Python path before running the
unit tests.
Out of the box SharpDevelop will actually use the unittest
library's test runner. This seems to work however if you
actually need to use the unittest2 test runner then you can
modify the following two files in the folder
AddIns\AddIns\BackendBindings\PythonBinding\TestRunner.
- sdtest.py
- sdtestrunner.py