Test (__tests__ dir and .github/workflows): propose to implement unittests and automation

[KemingHe]

Request Form

@ad1992

Issue

Current yarn test script gives placeholder echo statement in package.json

Request

Implement automated unittesting through vitest and GitHub Actions to run per PR and merge (push) to main, aligning with project setup.

Reason

I want to use this package and I want future versions to be bug-free when I npm update.

Plan

1. Accept this issue.
2. Assign @KemingHe , tag as test.
3. I will open a PR with ONLY adding the testing automation by end of day 07/26.
4. Review, refactor or merge, and apply this issue as simple default issue template if you want.

Edit: grammar

[ad1992]

@KemingHe sure please go ahead and raise the PR

[KemingHe]

@ad1992 Delivered and revised in #8. Edit: update status.