diff --git a/activerecord/test/cases/json_serialization_test.rb b/activerecord/test/cases/json_serialization_test.rb
index 3446e5e7f0..975acde096 100644
--- a/activerecord/test/cases/json_serialization_test.rb
+++ b/activerecord/test/cases/json_serialization_test.rb
@@ -200,6 +200,6 @@ class DatabaseConnectedJsonEncodingTest < ActiveRecord::TestCase
       2 => @mary
     }
 
-    assert_equal %({1: {"name": "David"}}), authors_hash.to_json(:only => [1, :name])
+    assert_equal %({"1": {"name": "David"}}), authors_hash.to_json(:only => [1, :name])
   end
 end