tests calcWH and calcXY

[imagineLife]

This is to increase code coverage

[STRML]

Hey, looks like the pre-merge checks are working properly now and you have a few small type errors. I can merge when they're fixed up. Thanks a ton for the contribution!

[imagineLife]

Hey @STRML 👋 Thanks for the note here -
In favor of trusting the type-checking, some js error-checking && error-validating test code is now removed from the code.
Also, a --coverage flag is included in the make test script here to begin ensuring code-coverage stays at least at its current threshold 🤞

[STRML]

Thanks a ton @imagineLife!