t.Errorf("User's updated at should be changed, old %v, new %v", user2.UpdatedAt.Format(time.RFC1123Z), user3.UpdatedAt.Format(time.RFC1123Z))
	}

	// update with gorm exprs
	if err := DB.Model(&user3).Updates(map[string]interface{}{"age": gorm.Expr("age + ?", 100)}).Error; err != nil {
		t.Errorf("Not error should happen when updating with gorm expr, but got %v", err)
	}
	var user4 User