- Create new class t/TestEnvironment.pm. A TestEnvironment instance
owns a temporary Git repo and a temporary Elixir database directory.
- Update t/100-basic.t to use TestEnvironment.
- Add constant MUST_SUCCEED so `run_produces_ok()` calls are more
self-documenting
- Added test helpers in t/TestHelpers.pm
- Added basic test of update.py and query.py in t/100-basic.t
- Updated README:
- Added automated-testing section
- Formatted identifiers (i.e., added backticks)