diff --git a/test/bson/ordered_hash_test.rb b/test/bson/ordered_hash_test.rb
index 1277fd9..b06f44f 100644
--- a/test/bson/ordered_hash_test.rb
+++ b/test/bson/ordered_hash_test.rb
@@ -88,6 +88,7 @@ class OrderedHashTest < Test::Unit::TestCase
 
     assert_equal [:c, :d], h1.keys
     assert_equal [3, 4], h1.values
+    assert h1.keys.id != h2.keys.id
   end
 
   def test_to_a_order_preserved