By Sergio Colque Ponce — Software Engineering, Universidad Privada de Tacna.
Full source code: github.com/srg-cp/design-principles-go
When people say "this code is well designed", they rarely mean it has clever tricks. They usually mean it is easy to change. New requirements arrive every week, and good design is what lets you absorb them without rewriting half the project.
In this article I take a small, very common requirement — "send a reminder to the user" — and I show how four classic design principles turn a fragile module into one that is open to change and easy to test. Everything is written in Go, and you can run it yourself from the repository linked above.
The requirement
