Add OAuth scopes

https://github.com/foodcoops/foodsoft/issues/582#issuecomment-442513237

spec/support/api_helper.rb

@@ -3,8 +3,28 @@ module ApiHelper
 
   included do
     let(:user) { create(:user) }
-    let(:api_access_token) { create(:oauth2_access_token, resource_owner_id: user.id).token }
+    let(:api_scopes) { [] } # empty scopes for stricter testing (in reality this would be default_scopes)
+    let(:api_access_token) { create(:oauth2_access_token, resource_owner_id: user.id, scopes: api_scopes&.join(' ')).token }
     let(:api_authorization) { "Bearer #{api_access_token}" }
+
+    def self.it_handles_invalid_token(method, path, params_block = ->{ api_auth })
+      context 'with invalid access token' do
+        let(:api_access_token) { 'abc' }
+        it { is_expected.to validate(method, path, 401, instance_exec(&params_block)) }
+      end
+    end
+
+    def self.it_handles_invalid_scope(method, path, params_block = ->{ api_auth })
+      context 'with invalid scope' do
+        let(:api_scopes) { ['none'] }
+        it { is_expected.to validate(method, path, 403, instance_exec(&params_block)) }
+      end
+    end
+
+    def self.it_handles_invalid_token_and_scope(*args)
+      it_handles_invalid_token(*args)
+      it_handles_invalid_scope(*args)
+    end
   end
 
   # Add authentication to parameters for {Swagger::RspecHelpers#validate}