Add daily email for 2023-12-16

Adding snapshot tests to Build Configs

src/content/daily-email/2023-12-16.md

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+---
+title: >
+  Adding snapshot tests to Build Configs
+pubDate: 2023-12-16
+permalink: >
+  archive/2023/12/16/adding-snapshot-tests-to-build-configs
+tags:
+  - software-development
+  - php
+  - symfony
+  - build-configs
+  - automated-testing
+  - test-driven-development
+---
+
+This week, I've started to add snapshot tests to the [Build Configs project][build configs].
+
+I had unit tests for the DTO validation to ensure the configuration was correct, but the main thing I wanted to test was I could run it for a given configuration file and get the expected files and contents to be generated.
+
+With snapshot tests, I generate the files for each configuration and compare them to a set that I know to be correct.
+
+If the files match, the tests pass, but, if they don't - such as a bug in the code, the tests will fail.
+
+This is the level that I want to be testing this project and that provides the most value.
+
+If a snapshot test fails, I can try to replicate the underlying issue in a unit test whilst also fixing the snapshot test.
+
+[build configs]: https://www.oliverdavies.dev/build-configs