test: Expand tests for built-in functions

[simicd]

Which issue does this PR close?

Closes #128

Rationale for this change

Improve test coverage for buit-in functions

What changes are included in this PR?

• Expand tests for math functions
• Expand tests for string functions
• Expand tests for hash functions
• Add tests for temporal functions

Are there any user-facing changes?

No

[simicd]

Thanks for running the GitHub Action, saw it was failing yesterday.

• Rebased branch to latest master
• Fix failing unit tests (change in data types)
• Ran formatter & linter so that GitHub Action job should pass now

[jdye64]

@simicd I don't have permissions to officially review but wanted to say changes look good. More test coverage is always a good thing

[simicd]

Thanks @jdye64! One question: When you want to update a branch after submitting a PR, do you rebase or just merge main into your branch? Asking because it seems like Actions require someone to trigger the workflow again, hope I didn't pick the wrong option by rebasing.

[martin-g]

I always prefer using git rebase for Pull Request branches. This way the commit history is cleaner.
Rebasing also makes it easier to use Squash and merge Github UI functionality.

The workflows should be triggered manually for first time contributors. Once your first PR is merged all following PRs will execute the checks automatically!

[andygrove]

LGTM. Thanks @simicd

[simicd]

Thanks for the review @andygrove and for the explanation @martin-g!