Add error model

lib/pragma/operation.rb

@@ -4,6 +4,7 @@
 
 require 'pragma/operation/version'
 require 'pragma/operation/base'
+require 'pragma/operation/error'
 
 require 'pragma/operation/response'
 require 'pragma/operation/response/not_found'
@@ -13,6 +14,7 @@
 require 'pragma/operation/response/ok'
 require 'pragma/operation/response/no_content'
 
+
 module Pragma
   # Operations provide business logic encapsulation for your JSON API.
   #

lib/pragma/operation/error.rb

@@ -0,0 +1,11 @@
+module Pragma
+  module Operation
+    class Error
+      def initialize(error_type:, error_message:, meta: {})
+        @error_type = error_type
+        @error_message = error_message
+        @meta = meta
+      end
+    end
+  end
+end

lib/pragma/operation/response/forbidden.rb

@@ -5,10 +5,10 @@ module Operation
     class Response
       class Forbidden < Response
         def initialize(
-          entity: {
+          entity: Error.new(
             error_type: :forbidden,
             error_message: 'You are not authorized to access the requested resource.'
-          },
+          ),
           headers: {}
         )
           super(status: 403, entity: entity, headers: headers)

lib/pragma/operation/response/not_found.rb

@@ -5,10 +5,10 @@ module Operation
     class Response
       class NotFound < Response
         def initialize(
-          entity: {
+          entity: Error.new(
             error_type: :not_found,
             error_message: 'The requested resource could not be found.'
-          },
+          ),
           headers: {}
         )
           super(status: 404, entity: entity, headers: headers)

lib/pragma/operation/response/unprocessable_entity.rb

@@ -7,13 +7,13 @@ class UnprocessableEntity < Response
         def initialize(entity: nil, headers: {}, errors: nil)
           fail ArgumentError, 'You cannot provide both :entity and :errors!' if entity && errors
 
-          entity ||= {
+          entity ||= Error.new(
             error_type: :unprocessable_entity,
             error_message: 'The provided resource is in an unexpected format.',
             meta: {
               errors: errors || {}
             }
-          }
+          )
 
           super(status: 422, entity: entity, headers: headers)
         end