Add value mapping for native enums

[sheinbergon]

Changes

Fixes #450

Add values_callable to allow for enum values to be inserted properly

Checklist

If this is a user-facing code change, like a bugfix or a new feature, please ensure that
you've fulfilled the following conditions (where applicable):

• You've added tests (in tests/) which would fail without your patch
• You've added a new changelog entry (in CHANGES.rst).

If this is a trivial change, like a typo fix or a code reformatting, then you can ignore
these instructions.

Updating the changelog

If there are no entries after the last release, use **UNRELEASED** as the version.
If, say, your patch fixes issue #123, the entry should look like this:

- Fix big bad boo-boo in task groups
  (`#123 <https://github.com/agronholm/sqlacodegen/issues/123>`_; PR by @yourgithubaccount)

If there's no issue linked, just link to your pull request instead by updating the
changelog after you've created the PR.

[coveralls]

coverage: 97.459%. remained the same
when pulling c8a8b9f on sheinbergon:enum-generation-value-mapping
into f4619eb on agronholm:master.

[sheinbergon]

@agronholm please have a look at this small fix

[agronholm]

Just wondering if it makes sense to add a test against the actual issue.

[sheinbergon]

Just wondering if it makes sense to add a test against the actual issue.

I'm not sure how you'd go about testing it with an actual database to the playing field. While I do think it's worth adding real E2E tests for this library , I feel it's an effort worthy of its own PR

[agronholm]

Just wondering if it makes sense to add a test against the actual issue.

I'm not sure how you'd go about testing it with an actual database to the playing field. While I do think it's worth adding real E2E tests for this library , I feel it's an effort worthy of its own PR

Using an SQLite database to add a record involving an enum would suffice I think.

[sheinbergon]

Just wondering if it makes sense to add a test against the actual issue.

I'm not sure how you'd go about testing it with an actual database to the playing field. While I do think it's worth adding real E2E tests for this library , I feel it's an effort worthy of its own PR

Using an SQLite database to add a record involving an enum would suffice I think.

So that's a real database, nonetheless. Setting any database is not an issue. Building E2E test infrastructure is a bit of a bigger task I'd like to properly design at some point. We'll get there