diff --git a/ChangeLog b/ChangeLog
index 2a1987feed..ac6a27621b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Thu Apr 24 22:55:22 2014  Tanaka Akira  <akr@fsij.org>
+
+	* bootstraptest/test_io.rb: Add etc.so to $" before require 'tmpdir'.
+
 Thu Apr 24 21:09:55 2014  Kazuhiro NISHIYAMA  <zn@mbf.nifty.com>
 
 	* man/ruby.1: fix broken link.
diff --git a/bootstraptest/test_io.rb b/bootstraptest/test_io.rb
index f7360f34b3..881431c93e 100644
--- a/bootstraptest/test_io.rb
+++ b/bootstraptest/test_io.rb
@@ -42,6 +42,7 @@ assert_finish 1, %q{
 }
 
 assert_equal 'ok', %q{
+  $" << 'etc.so'
   require 'tmpdir'
   begin
     tmpname = "#{Dir.tmpdir}/ruby-btest-#{$$}-#{rand(0x100000000).to_s(36)}"
@@ -58,6 +59,7 @@ assert_equal 'ok', %q{
 }
 
 assert_equal 'ok', %q{
+  $" << 'etc.so'
   require 'tmpdir'
   begin
     tmpname = "#{Dir.tmpdir}/ruby-btest-#{$$}-#{rand(0x100000000).to_s(36)}"