Implement unit tests

[freespace]

Tests would be useful to ensure nothing is breaking. My preference would be nose:

https://pypi.python.org/pypi/nose/1.3.7

[grzanka]

BTW - do you have some of travis/wercker/appveyor account ? If yes, it would be nice to run there the tests.

To maintain python3/2 compatibility I'd use tox - what do you think ?

[freespace]

Don't have an account on any CI system.

Using tox seems like a good idea, though unless we have py2/3 dependent code paths we should be fine testing in either 2 or 3?