More than testing — writing unit tests for better design

Use unit tests to inform the design of code

This article was originally published on my website — https://kislayverma.com/programming/more-than-testing-writing-unit-tests-for-better-design/

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For the first nearly ten years of my programming career, I hardly wrote any unit tests. I wrote a lot of code, and tested almost all of it by running it and testing for end-to-end behaviour, mostly manually. However , as I started inheriting larger and larger codebases and projects across multiple teams in my role as an architect, I began to see why everyone went on about unit testing. There usually isn’t a faster way to know that the code you are writing is safe and works as expected. This is a huge safety net during refactoring complicated code. It is certainly cheaper than having to start a service with its datastore and other attending paraphernalia just to see if a small change is fine. Good unit test coverage also serves as a good and fast way of ensuring that you are shipping the right thing in the land of CI-CD etc. Running integration tests which require elaborate set-up if you want to deploy very often can be very expensive on the infra.