Add basic tests

[ahalterman]

Add two basic tests of the pipeline with the pytest framework. Future modifications to the pipeline should come with associated tests of their functionality and shouldn't break existing tests.

These tests can be run by running py.test from the command line inside the tests/ directory. pip install pytest if it's not installed.

[johnb30]

Couple things:

1) Might want to add some line breaks/formatting into those long lines. Just for readability.

2) While you're writing tests you might consider setting up Travis CI integration. I might need to be the one to turn that on, but if you setup the .travis.yml file I'll turn it on.

[ahalterman]

Added the .travis.yml file and cleaned up the formatting by putting the different fields on their own lines. I didn't want to mess with formatting each string, so it's not perfectly 80 characters.

[johnb30]

👍