Feature request: Authentication support for integration test using GraphQLSpec trait

[orr3]

Using Spring Security together with GORM GraphQL we want to be able to add authentication headers in our integration tests to validate our app security, data integrity and tenancy that has been setup with GraphQL interceptors and Spring Security configuration.

This can be done by attaching GET parameter /graphql?access_token=XXX or allowing developer to add HTTP headers to RxHttpClient.