diff --git a/core/io/shared/new.rb b/core/io/shared/new.rb
index cba5f33eb..f074fa323 100644
--- a/core/io/shared/new.rb
+++ b/core/io/shared/new.rb
@@ -271,7 +271,6 @@
   it "accepts an :autoclose option" do
     @io = IO.send(@method, @fd, 'w', autoclose: false)
     @io.should_not.autoclose?
-    @io.autoclose = true
   end
 
   it "accepts any truthy option :autoclose" do