Adds unit tests for all situations

I had some problem with the mocking class, but this post
explained to me why it wasn't working:
http://alexmarandon.com/articles/python_mock_gotchas/
Reformats code so pep8 is happy
Fix syntax error
Introduce path variables for mocking paths
Adds method documentation to validate command method
Merge branch 'master' into add-validation-command
Merge pull request #5 from wercker/add-validation-command

Add validation command