Add the error response type to the library

lib/qmp_client/messages.rb

@@ -2,6 +2,7 @@ require 'json'
 
 require 'qmp_client/messages/command'
 require 'qmp_client/messages/greeting'
+require 'qmp_client/messages/error'
 require 'qmp_client/messages/event'
 require 'qmp_client/messages/query'
 require 'qmp_client/messages/reply'
@@ -36,6 +37,7 @@ module QMPClient
       return Event::build(hsh) if Event::represents?(hsh)
       return Command::build(hsh) if Command::represents?(hsh)
       return Query::build(hsh) if Query::represents?(hsh)
+      return Error::build(hsh) if Error::represents?(hsh)
       return Greeting::build(hsh) if Greeting::represents?(hsh)
 
 

lib/qmp_client/messages/error.rb

@@ -0,0 +1,48 @@
+require 'qmp_client/messages/message'
+
+module QMPClient
+  module Messages
+    class Error < Message
+      attr_reader :request_id
+      attr_reader :error_class
+      attr_reader :data
+      attr_reader :desc
+
+      # Does the hash represent a Command?
+      def self.represents?(hsh)
+        super(hsh) &&
+          (hsh.keys - %w|id error|).empty? && hsh['error'].is_a?(Hash) &&
+          hsh['error']['class'].is_a?(String) &&
+          hsh['error']['data'].is_a?(Hash) &&
+          hsh['error']['desc'].is_a?(String)
+      end
+
+      def ==(other)
+        other.is_a?(Error) && [
+            :request_id, :error_class, :data, :desc
+          ].all? {|m| self.send(m) == other.send(m) }
+      end
+
+      def self.build(hsh)
+        err = hsh['error']
+        new(hsh['id'], err['class'], err['data'], err['desc'])
+      end
+
+      def initialize(request_id, err_kls, data, desc)
+        @request_id = request_id
+        @error_class = err_kls
+        @data = data
+        @desc = desc
+      end
+
+      def to_hash
+        { 'id' => request_id,
+          'error' => {
+            'class' => error_class, 'data' => data, 'desc' => desc
+          }
+        }
+      end
+
+    end
+  end
+end