This is an excellent discussion on programming in general:
One thing that stood out is the thought that quality (and thus tests) need to be built in (during development). The other is that feedback loops are important (again tests). When you develop a new feature, do you develop an end-to-end (E2E) test as part of the development? If you make this your practice, then as a system grows, you’ll also have tests that help ensure you are not breaking things, and these tests can even be extended to ensure a production system is operating correctly. Good stuff and dovetails nicely with a book I just finished: The Phoenix Project – more on that later …