diff --git a/ChangeLog b/ChangeLog
index c5a581c7ca..7d0fd38cdd 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Sun Oct 24 14:13:50 2010  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* lib/test/unit.rb (Test::Unit::Mini#run_test_suites): ensure
+	  output sync mode to be restored.
+
 Sun Oct 24 14:11:16 2010  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* vm.c (vm_define_method): defined method is run with the default
diff --git a/lib/test/unit.rb b/lib/test/unit.rb
index f722205fa4..b5b9f719b1 100644
--- a/lib/test/unit.rb
+++ b/lib/test/unit.rb
@@ -156,11 +156,18 @@ module Test
       def self.autorun
         at_exit {
           Test::Unit::RunCount.run_once {
-          exit(Test::Unit::Mini.new.run(ARGV) || true)
-        }
+            exit(Test::Unit::Mini.new.run(ARGV) || true)
+          }
         } unless @@installed_at_exit
         @@installed_at_exit = true
       end
+
+      def run_test_suites(*args)
+        old_sync = @@out.sync if @@out.respond_to?(:sync=)
+        super
+      ensure
+        @@out.sync = old_sync if @@out.respond_to?(:sync=)
+      end
     end
   end
 end