diff --git a/test/ruby/test_optimization.rb b/test/ruby/test_optimization.rb
index b42314b765..e6163c06e2 100644
--- a/test/ruby/test_optimization.rb
+++ b/test/ruby/test_optimization.rb
@@ -705,7 +705,7 @@ class TestRubyOptimization < Test::Unit::TestCase
       def foo &b
       end
       h1 = {}; h2 = {}
-      ObjectSpace.count_objects(h1) # reharsal
+      ObjectSpace.count_objects(h1) # rehearsal
       ObjectSpace.count_objects(h1)
       foo{}
       ObjectSpace.count_objects(h2)