add support for enums in sqlalchemy ChoiceType

[metheoryt]

Hi! I've found that I cannot use python enums with sqlalchemy_utils's ChoiceType, so here's my solution for it

[coveralls]

Coverage increased (+0.02%) to 97.343% when pulling 640cd17 on metheoryt:patch-1 into 8ea2086 on graphql-python:master.

[coveralls]

Coverage decreased (-0.2%) to 97.104% when pulling 5117e53 on metheoryt:patch-1 into c89cf80 on graphql-python:master.

[jnak]

Thanks for sending a PR. Would you mind updating the tests in test_converter.py so both cases are tested?

You can see how to run the tests locally here: https://github.com/graphql-python/graphene-sqlalchemy/blob/master/CONTRIBUTING.md

[jnak]

Oops - I didn't see your update until now. Thanks for adding the tests. I have one minor comment about a deleted TODO but I'm fine punting on it if you don't have time to put it back.

Since it seems you are using ChoiceType, you may be interested in addressing the TODO in a later PR. It should make it a lot easier to deal with auto-generated Enums (see my comment).

[jnak]

Oops - completely fell off my radar. Sorry for the delay.

[jnak]

@metheoryt Btw in case you're interested, here is more context on the TODO. The enums auto-generated by ChoiceLabel are not as clean and robust as other enum columns:

• the name of the enum include the the table and the column name
• the name of the enum cannot be customized
• a duplicated enum is created (with a different name) if the ChoiceType is shared across multiple columns

This PR added proper support for enums but did not include ChoiceType. I think it would be quite straightforward to have ChoiceType leverage the same infrastructure.

Cheers