Add basic request spec for /.well-known/oauth-authorization-server endpoint

spec/requests/well_known/oauth_metadata_spec.rb

@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+describe 'The /.well-known/oauth-authorization-server request' do
+  it 'returns http success with valid JSON response' do
+    get '/.well-known/oauth-authorization-server'
+
+    expect(response)
+      .to have_http_status(200)
+      .and have_attributes(
+        media_type: 'application/json'
+      )
+
+    expect(body_as_json).to match(
+      a_hash_including(
+        # FIXME: Include tests for the important URLs (for some reason routing
+        # was generating mismatching URLs between the serializer and the tests)
+        scopes_supported: Doorkeeper.configuration.scopes.map(&:to_s)
+      )
+    )
+  end
+end