--- test/rdoc/test_rdoc_ri_driver.rb.orig	2010-07-10 17:23:09.000000000 -0700
+++ test/rdoc/test_rdoc_ri_driver.rb	2010-07-10 17:23:17.000000000 -0700
@@ -499,6 +499,10 @@
     driver = RDoc::RI::Driver.new
 
     io = Object.new
+    def io.tty?; false; end
+
+    assert_instance_of @RM::ToBs, driver.formatter(io)
+
     def io.tty?; true; end
 
     assert_instance_of @RM::ToAnsi, driver.formatter(io)