fix "RangeError: 256 out of char range", because Integer#chr handles …

…255 at most, but the value to be 256.

lib/apn_on_rails/app/models/apn/group_notification.rb

@@ -71,7 +71,7 @@ def to_apple_json
   # Creates the binary message needed to send to Apple.
   def message_for_sending(device)
     json = self.to_apple_json
-    message = "\0\0 #{device.to_hexa}\0#{json.length.chr}#{json}"
+    message = "\0\0 #{device.to_hexa}#{[json.length].pack('n')}#{json}"
     raise APN::Errors::ExceededMessageSizeError.new(message) if message.size.to_i > 256
     message
   end

spec/apn_on_rails/app/models/apn/group_notification_spec.rb

@@ -61,6 +61,18 @@
       }.should raise_error(APN::Errors::ExceededMessageSizeError)
     end
 
+    it 'should not raise any error if the payload is not too big' do
+      app = AppFactory.create
+      device = DeviceFactory.create({:app_id => app.id})
+      group =   GroupFactory.create({:app_id => app.id})
+      device_grouping = DeviceGroupingFactory.create({:group_id => group.id,:device_id => device.id})
+      noty = GroupNotificationFactory.new(:group_id => group.id, :sound => true, :badge => nil)
+      noty.stub(:to_apple_json).and_return('_' * 256)
+      lambda {
+        noty.message_for_sending(device)
+      }.should_not raise_error
+    end
+
   end
 
 end