[aws|dns] Preserves change_id. Support for checking sync status via reload.

lib/fog/aws/models/dns/record.rb

@@ -17,6 +17,7 @@ module Fog
         attribute :status,        :aliases => ['Status']
         attribute :created_at,    :aliases => ['SubmittedAt']
         attribute :alias_target,  :aliases => ['AliasTarget']
+        attribute :change_id,     :aliases => ['Id']
 
         def initialize(attributes={})
           self.ttl ||= 3600
@@ -55,6 +56,24 @@ module Fog
           true
         end
 
+        # Returns true if record is insync.  May only be called for newly created or modified records that
+        # have a change_id and status set.
+        def insync?
+          requires :change_id, :status
+          status == 'INSYNC'
+        end
+
+        def reload
+          # If we have a change_id (newly created or modified), then reload performs a get_change to update status.
+          if change_id
+            data = connection.get_change(change_id).body
+            merge_attributes(data)
+            self
+          else
+            super
+          end
+        end
+
         private
 
         def zone=(new_zone)

tests/aws/models/dns/record_tests.rb

@@ -8,11 +8,23 @@ Shindo.tests("Fog::Dns[:aws] | record", ['aws', 'dns']) do
   params = { :name => @zone.domain, :type => 'A', :ttl => 3600, :value => ['1.2.3.4'] }
 
   model_tests(@zone.records, params, false) do
+
+    # Newly created records should have a change id
+    tests("#change_id") do
+      returns(true) { @instance.change_id != nil }
+    end
+
+    # Waits for changes to sync to all Route 53 DNS servers.  Usually takes ~30 seconds to complete.
+    tests("#insync? - may take a minute to complete...").succeeds do
+      @instance.wait_for { insync? }
+    end
+
     tests("#modify") do
       new_value = ['5.5.5.5']
       returns(true) { @instance.modify(:value => new_value) }
       returns(new_value) { @instance.value }
     end
+
   end
 
   tests("zones#destroy").succeeds do