Improve unit test coverage

[rgwozdz]

Each monorepo package has some degree of test coverage. Note that some packages include "integration" tests as well as specific unit tests. This is a legacy of early development on these packages, where initial tests were geared towards specific feature functionality (e.g., filtering) rather than specific function input/output. Over time, we have moved towards a unit approach on individual packages, and are now moving integration tests to the root level of the monorepo.

Ideally, we want to achieve 100% unit test coverage on all packages. You can test unit coverage specifically with:

npm run test:cov:unit

Then review the coverage report at:

coverage_unit/index.html

This report will reveal where tests could and should be added.