diff --git a/lib/nose/util.rb b/lib/nose/util.rb
index 5b6e2834..e43d7ea7 100644
--- a/lib/nose/util.rb
+++ b/lib/nose/util.rb
@@ -150,7 +150,7 @@ def subtype_name(name_case: :snake)
     # Convert camel case class names to an array
     # @return [Array<String>]
     def name_array(cls)
-      frozen_name = cls.name
+      frozen_name = cls.name.dup
       frozen_name.gsub!(/^.*::/, '')
       frozen_name.gsub!('ID', 'Id')
       frozen_name.freeze