It's more of a constant testing mentality, from the clients, managers and developers. It's a bit like security.. you can't stop in the middle of the development

It's more of a constant testing mentality, from the clients, managers and developers. It's a bit like security.. you can't stop in the middle of the development and say: Hey, let's make that app. secure. It's a continual way of thinking. How you test it, however, is really application dependent. For sure, a thing that I find the most important in the agile way, is to let the client use the app as much as possible and as sooner as possible. This way, they practically test the application for you and help you focus on the right things.