Update the GitHub tests to use the new hosting service test helpers.
Review Request #9871 — Created April 10, 2018 and submitted — Latest diff uploaded
This updates the GitHub test suite to use the new helpers for hosting
service unit tests, which provide better, more consistent checks with
simpler code. The results of all HTTP requests are checked, ensuring
we're calling what we expect and that behavior doesn't change in the
future.
Unit tests pass.