make sure we have a value in migrated_at

activerecord/test/cases/migration_test.rb

@@ -1507,7 +1507,7 @@ def test_migration_row_includes_name_and_timestamp
 
       rows = conn.select_all("SELECT * FROM #{conn.quote_table_name(sm_table)}")
       rows.each do |row|
-        assert_match(/^2\d\d\d-/, row["migrated_at"].to_s, "missing migrated_at")
+        assert_not_nil(row["migrated_at"], "missing migrated_at")
       end
       assert_equal "people_have_last_names",  rows[0]["name"]
       assert_equal "we_need_reminders",       rows[1]["name"]