resolve_type: Tests for Interface

[tony]

Hi,

I am trying to get def resolve_type working with Interface. My goal is to get this functioning (if it's the case it's not working). Forgive me if I'm misunderstanding how resolve_type works! Hopefully this test helps assure the the example we document in the interfaces.rst documentation will work.

As a way to create a minimal example, I've created a PR, but not sure if I'm correct on it yet. I think we should probably put it in test_query and also test for the resolved data + field. I also tried putting it in test_interface.py, but that may be too low level for resolve_type to run.

Here are some of the places I've researched prior to coming here:

• https://medium.com/the-graphqlhub/graphql-tour-interfaces-and-unions-7dd5be35de0d resolveType in graphql
• Help with constructing an arbitrary ObjectType #699: Example of resolve_type
• resolve_type vs is_type_of rmosolgo/graphql-ruby#1267 (resolve_type vs is_type_of: Note, we currently do have a test for is_type_of, but not resolve_type).
• Other related resolve_types mentions buried in the tracker: Document resolvers #654, Rename resolve_type method #775

[tony]

This issue was due to me using a field named type. I'm abandoning this PR since my case is probably solved by #775