diff --git a/ChangeLog b/ChangeLog
index 5484d2f375..eb439a8442 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Mon Oct 31 19:14:11 2011  Tanaka Akira  <akr@fsij.org>
+
+	* test/resolv/test_dns.rb: don't check maximum sleeped time.
+	  ruby doesn't guarantee the maximum time because it is not a
+	  realtime application.
+
 Mon Oct 31 13:10:06 2011  NAKAMURA Usaku  <usa@ruby-lang.org>
 
 	* win32/win32.c (setfl): extract from fcntl().
diff --git a/test/resolv/test_dns.rb b/test/resolv/test_dns.rb
index 3fce206c6b..9ae0df404f 100644
--- a/test/resolv/test_dns.rb
+++ b/test/resolv/test_dns.rb
@@ -116,7 +116,7 @@ class TestResolvDNS < Test::Unit::TestCase
       }
       diff = Time.now - start
       assert rv.empty?, "unexpected: #{rv.inspect} (expected empty)"
-      assert_in_delta 0.1, diff, 0.05
+      assert_operator 0.1, :<=, diff
 
       rv = Resolv::DNS.open(:nameserver_port => [[host, port]]) {|dns|
         dns.timeouts = [ 0.1, 0.2 ]
@@ -125,7 +125,7 @@ class TestResolvDNS < Test::Unit::TestCase
       }
       diff = Time.now - start
       assert rv.empty?, "unexpected: #{rv.inspect} (expected empty)"
-      assert_in_delta 0.3, diff, 0.05
+      assert_operator 0.3, :<=, diff
     }
   end