Add support for external `$ref`s

[JerrodCarpenter]

Hey y'all, interested in integrating this very cool gem. I'm getting an error when attempting to use assert_conform_schema.

• Ruby 3.3.0
• Rails 7.1.5.1
• Minitest 5.15.0
• Skooma 0.3.4
• JSONSkooma 0.2.5

> assert_conform_schema(200)
NoMethodError: undefined method `evaluate' for nil
from /.asdf/installs/ruby/3.3.0/lib/ruby/gems/3.3.0/gems/json_skooma-0.2.5/lib/json_skooma/keywords/core/ref.rb:14:in `evaluate'

It may be a set up thing, but assert_is_valid_document(skooma_openapi_schema) evaluates just fine.

This line appears to be generating the error.

[eliasjpr]

Same here

[skryukov]

Sorry for super late response, do you have any $ref's in your specs?

[JerrodCarpenter]

Sorry for super late response, do you have any $ref's in your specs?

@skryukov that's right. We use them heavily to break up the size of files.