In this chapter, you learned how to accept and validate, submitted input from a user using Validateur. You also learned how to create reusable validators, thus reducing the amount of code you'd have to write in the future. Finally, we adjusted our signup.html template to use a new Selmer tag—the cycle tag—to loop through our errors and render each one out appropriately. However, we lived a little dangerously: we did some refactoring, but had no way of ensuring that what we refactored worked until we tested it in the browser. In the next chapter, we'll take a look at how we could have written some tests to validate this for us.