When we talk about Agile software development, it’s impossible not to mention tests.
The ‘fail fast’ principle also entails test-driven development and continuous delivery. We no longer wait to have the application in a test environment and someone responsible for clicking in a bunch of buttons until they figure out that software doesn’t work as expected. We now have pipelines that allow us to run automated tests before our application gets to production, lessening the need for manual tests and making developers equally responsible for the quality of software they’re developing.
However, there are still lots of questions about how and when to test.