[Feature request] Add test coverage for all of the parsing logic.

[mrhappyasthma]

• Add more canned responses to the TestData/ subfolder
• Add python tests to verify testing logic

We could consider even trying to write end-to-end tests that actually fetch data from a production URL, too. But then the asserts need to be fuzzy since we won't be able to have an expected output that's fixed.

[mrhappyasthma]

Folding this in to #59. I think functionality tests are more important than parsing at this stage.