valmik-patel

https://github.com/dssg/aequitas/pull/175 I created this draft PR to add testing to the library using `pytest`. Currently, the script will run tests defined in the `tests` folder and output a coverage report....

@sgpjesus this is ready for review - I had to update the `xhtml2pdf` dependency version to get the preexisting tests to work - I also had to add `fastparquet` as...

@sgpjesus I've removed the unused import and added more tests to ensure 100% coverage for `GenericDataset`. You can review it again now. Thanks!