Improve test coverage.

We're always looking to improve our test coverage, whether it's through a new simple unit test, expansion of an existing test bench, or whatever.

NOTE: While line coverage is a decent indicator of test coverage, another way to think about test coverage is in the problem/input space. You may have achieved 100% line coverage but still be missing coverage of key/corner cases. (This would indicate a flaw or lack in the code itself.)

No file, module, failing test, or behavior is named. Start by inspecting the repository's Python utilities and current test setup, then identify a specific uncovered behavior or edge case; done means adding focused coverage for that case and confirming the test suite passes.

Written by the indexing model from the issue text.