test: more tests, functional tests, replace ava to vitest & fixes

[endes0]

The main goal of this PR is to add new tests(mostly functional) and fix/refactor the current tests. It also fixes a lot of bugs and discovers new ones (#76 #75).

Closes #35

[oxcabe]

Great work! You should merge the main branch into this one for the CI workflow to pass. I changed it to use yarn, as it was still using npm.

[oxcabe]

For the changes I am requesting here, we can skip the test to describe/it ones so we can keep advancing with the general refactor.

If we choose to skip those changes, it should still be referenced into a new issue and addressed in the future, where we can either reimplement the tests à la Rust or commit with the describe approach.

[endes0]

For the changes I am requesting here, we can skip the test to describe/it ones so we can keep advancing with the general refactor.

If we choose to skip those changes, it should still be referenced into a new issue and addressed in the future, where we can either reimplement the tests à la Rust or commit with the describe approach.

I did not implement the tests in the correct way (with describe/it) as the tests in ava did not use them and I rushed the change from ava to vitest. I prefer to skip those changes at the moment, because I am behind in my plannings. As you suggested, I can open an issue about this.