test: add string function test cases

[richtia]

No description provided.

[richtia]

The like function is having some issues: Reason: like requires second argument to be a constant of type VARCHAR

postgres does not support negative start positions for substring.

[westonpace]

Let's mark pyvelox as unsupported for like for now and we can add a "requires_constant" option later when they come up with a newer release.

Let's open an issue for this before we merge this.

Let's make another PR to add a new option to substrait specifying behavior of negative start for substring. Choices are:

• Wrap from the end (duckdb, sqlite?)
• Go left past the beginning (postgres)
• Throw an error (???)

For this PR maybe update the substring function to have some examples of each and use required_options similar to how we handle overflow in addition.

[richtia]

Let's mark pyvelox as unsupported for like for now and we can add a "requires_constant" option later when they come up with a newer release.

Let's open an issue for this before we merge this.

Let's make another PR to add a new option to substrait specifying behavior of negative start for substring. Choices are:

• Wrap from the end (duckdb, sqlite?)
• Go left past the beginning (postgres)
• Throw an error (???)

For this PR maybe update the substring function to have some examples of each and use required_options similar to how we handle overflow in addition.

1. Created a clickup task for adding the requires constant option.
2. Opened substrait PR for negative start in substrings: feat: add options to substring for start parameter being negative substrait#508
3. Added the required_options in this PR