Write Tests Before Bug Fixes

What is the best way to prove that your bug fix works? Well, you test it. How do you make sure your bug fix keeps working years into the future? You write a test for it.

Specifically, you want to write a test that can reproduce the bug. Only once you've been able to do this, do you actually try to fix the bug. There are several of benefits for using this approach to fixing bugs:

Depending on the application or system you are working, writing tests might not be easy or might take too much time. If so, then that is a hint that the application or system you are working on might be so tightly coupled, that you cannot write a small “test” to test a specific part of the code. You should look into decoupling classes and making their methods smaller and modular, to make it easier to test various parts of the application. If you want to learn more about making your code easier to test, I suggest learning about SOLID Principles and looking into Test-Driven Development.

When I started out working professionally as a software developer, I actually didn't write any tests. I would just write code and test my changes manually. Nowadays, I feel uncomfortable about any code changes that I don't have tests for.

Tags: #Tests