Add daily email for 2025-02-10

Refactoring and Test-Driven Development

source/_daily_emails/2025-02-10.md

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+---
+title: Refactoring and Test-Driven Development
+date: 2025-02-10
+permalink: daily/2025/02/10/refactoring
+tags:
+  - software-development
+cta: ~
+snippet: |
+  How does refactoring work whilst doing test-driven development?
+---
+
+To do test-driven development, you start by writing a test which, because you're testing code that doesn't exist, will fail.
+
+The objective is to get the get the test to pass.
+
+You want to write just enough code to get the test to pass.
+
+It can be the simplest and naive code possible as long as it gets the tests to pass.
+
+Once the test passes, you can refactor and change the code in any way you want.
+
+This may be changing from a `foreach` loop to using a function like `array_map` or `array_reduce`, or splitting logic into separate classes.
+
+You may refactor your refactor and decide that a name or approach isn't correct and change it.
+
+You may split your code into service classes and then decide to use commands or actions.
+
+You can make whatever changes you want as long as the tests continue to pass.
+
+The implementation can change, but the outcome stays the same.