Feature/first unit tests

Here's the beginning of adding unit tests. There is still a good bit of work to do to improve coverage (currently 33.6% coverage by line).

Also, this PR depends on #2.
Can you explain this a bit more?  My goal here was simply to include the hdfs information in the ``toString``. This was important to make the output more useful. Do you have any thoughts on a better way to display this info?