You typically don&#x27;t feel the pain of not having tests until your app starts to get big and&#x2F;or starts to have lots of developers. That simple assert :success could catch a regression because you were using meta search while on rails 3 and now it doesn&#x27;t work on rails 4. You also don&#x27;t feel the pain of end-to-end testing until you rely on them too much and they are fickle, and hard to maintain.