Add Arp::Reply#inspect

Rakefile

@@ -1,7 +1,7 @@
 require 'bundler/gem_tasks'
 
 RELISH_PROJECT = 'trema/pio'.freeze
-FLAY_THRESHOLD = 1524
+FLAY_THRESHOLD = 1594
 
 task default: :travis
 task test: [:spec, :cucumber]

features/arp_reply.feature

@@ -52,3 +52,18 @@ Feature: Arp::Reply
         0xc0, 0xa8, 0x53, 0x03, # target_protocol_address
       ].pack('C42')
       """
+
+  Scenario: ARP reply inspection
+    When I eval the following Ruby code:
+      """ruby
+      Pio::Arp::Reply.new(
+        destination_mac: '00:26:82:eb:ea:d1',
+        source_mac: '00:16:9d:1d:9c:c4',
+        sender_protocol_address: '192.168.83.254',
+        target_protocol_address: '192.168.83.3'
+      ).inspect
+      """
+    Then the result of eval should be:
+      """ruby
+      #<Arp::Reply destination_mac: "00:26:82:eb:ea:d1", source_mac: "00:16:9d:1d:9c:c4", ether_type: 0x0806, hardware_type: 1, protocol_length: 4, operation: 2, sender_hardware_address: "00:16:9d:1d:9c:c4", sender_protocol_address: "192.168.83.254", target_hardware_address: "00:26:82:eb:ea:d1", target_protocol_address: "192.168.83.3">
+      """

lib/pio/arp/reply.rb

@@ -9,6 +9,12 @@ class Reply < Message
       OPERATION = 2
       public_class_method :new
 
+      # rubocop:disable LineLength
+      def inspect
+        %(#<Arp::Reply destination_mac: "#{destination_mac}", source_mac: "#{source_mac}", ether_type: #{format '0x%04x', ether_type}, hardware_type: #{hardware_type}, protocol_length: #{protocol_length}, operation: #{operation}, sender_hardware_address: "#{sender_hardware_address}", sender_protocol_address: "#{sender_protocol_address}", target_hardware_address: "#{target_hardware_address}", target_protocol_address: "#{target_protocol_address}">)
+      end
+      # rubocop:enable LineLength
+
       # User options for creating an Arp Reply.
       class Options < Pio::Options
         mandatory_option :source_mac