add tests for LONGDATETIME parsing/encoding

[Connum]

Description

add tests for parsing and encoding the LONGDATETIME type

Motivation and Context

This was not tested before, and a FIXME comment suggested to do so once it was implemented (which it has been for a long time).

How Has This Been Tested?

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Testing

Checklist:

• I did npm run test and all tests passed green (including code styling checks).
• I have added tests to cover my changes.
• My change requires a change to the documentation.
• I have updated the README accordingly.
• I have read the CONTRIBUTING document.

[ILOVEPIE]

This looks good, but we should probably finish implementing LONGDATETIME, or at least add it to the issue tracker. We should also start maintaining a separate issues list on trello or github projects.

[Connum]

we should probably finish implementing LONGDATETIME

I already looked into that but we'd need to use BigInt(), which means we would either loose backward compatibility or have to use a library to handle the 64bit timestamps. All that for an issue that we'll face in 15 years from now, where it should be possible to use BigInt() by then.

But yes, we should definitely keep track of these things!