HOD does not have any unit tests in place currently. This issue is to decide on a framework that would be effective for our python code base. Something on the lines of pyUnit would be good. The fix should put in place any dependencies needed for running the tests, and should also define some tests that demonstrate how to write further tests. We would not be defining a complete unit test suite for the entire code base right now, but would incrementatlly add tests as changes are made.