Fix unit test regressions on Python 3.
Review Request #1841 — Created Feb. 2, 2020 and updated
We had a few unit tests that were mixing string types, causing failures on Python 3. These are pretty basic mistakes that were limited to the test cases. This change fixes those. Testing Done: Unit tests pass on Python 2.7, 3.6, and 3.7. Reviewed at https://reviews.reviewboard.org/r/10866/