Checks for defined?(request) on Helper#exclude_visitor?

Author: andrehjr

lib/split/helper.rb

@@ -122,7 +122,7 @@ def ab_user
     end
 
     def exclude_visitor?
-      instance_exec(request, &Split.configuration.ignore_filter) || is_ignored_ip_address? || is_robot? || is_preview?
+      defined?(request) && (instance_exec(request, &Split.configuration.ignore_filter) || is_ignored_ip_address? || is_robot? || is_preview?)
     end
 
     def is_robot?