add regression test. Closes #18400.

1 files changed, 6 insertions, 0 deletions

diff --git a/activerecord/test/cases/persistence_test.rb b/activerecord/test/cases/persistence_test.rb
index 2803ad2de0..7c281a95b7 100644
--- a/activerecord/test/cases/persistence_test.rb
+++ b/activerecord/test/cases/persistence_test.rb
@@ -366,6 +366,12 @@ class PersistenceTest < ActiveRecord::TestCase
     end
   end
 
+  def test_update_does_not_run_sql_if_record_has_not_changed
+    topic = Topic.create(title: 'Another New Topic')
+    assert_queries(0) { topic.update(title: 'Another New Topic') }
+    assert_queries(0) { topic.update_attributes(title: 'Another New Topic') }
+  end
+
   def test_delete
     topic = Topic.find(1)
     assert_equal topic, topic.delete, 'topic.delete did not return self'