diff --git a/ChangeLog b/ChangeLog
index abb6cc599d..abf228a8d3 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Wed Dec 15 11:19:33 2010  NAKAMURA Usaku  <usa@ruby-lang.org>
+
+	* test/zlib/test_zlib.rb (test_to_io): forgotten to fix with r30201.
+
 Wed Dec 15 11:07:34 2010  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* io.c (simple_sendfile): enable on Mac OS X.
diff --git a/test/zlib/test_zlib.rb b/test/zlib/test_zlib.rb
index bff616a235..56940ace8c 100644
--- a/test/zlib/test_zlib.rb
+++ b/test/zlib/test_zlib.rb
@@ -237,8 +237,9 @@ if defined? Zlib
       t.close
       Zlib::GzipWriter.open(t.path) {|gz| gz.print("foo") }
 
-      f = Zlib::GzipReader.open(t.path)
-      assert_kind_of(IO, f.to_io)
+      Zlib::GzipReader.open(t.path) do |f|
+        assert_kind_of(IO, f.to_io)
+      end
     end
 
     def test_crc