While at Tinfoil Security, I wrote and released a small open source lib to help unit test GraphQL query documents against an Absinthe API. It requires no Plug.Conns and removes lots of boilerplate using macros.

You can read more about it here:

https://www.tinfoilsecurity.com/blog/wormwood-graphql-testing

And check out the code here:

https://github.com/tinfoil/wormwood