Split Tests into Separate Files

[chao-mu]

I sat down to write some tests and was alarmed at the test file being thousands of lines long. So I split it up. Is this something you'd want? Tests still run locally.

I didn't commit it, but I wrote this script for generating test coverage.

#!/usr/bin/env sh

# Usage: scripts/generate-coverage-report.sh

coverage run -m unittest discover
coverage html
coverage report
echo "## Open htmlcov/index.html for detailed breakdown ##"