daily-email: add 2023-05-06

src/content/daily-email/2023-05-06.md

@@ -0,0 +1,21 @@
+---
+title: >
+  Why it's important to see the test fail
+pubDate: 2023-05-06
+permalink: >
+  archive/2023/05/06/why-its-important-to-see-the-test-fail
+tags:
+  - automated-testing
+  - test-driven-development
+---
+
+With automated testing and test-driven development, it's important to see a test fail.
+If a test passes straight away, how do you know that you're testing the right thing? You could be accidentally testing a different piece of functionality, or it could be a false positive.
+
+If the functionality already exists, do you need another test for it?
+
+When you see a test fail, you know that the functionality hasn't been implemented, that you're testing the correct thing, and you have a clear goal to work towards.
+
+If you're fixing a bug, writing a test and seeing it fail verifies the bug exists and that, once the bug is fixed, the test will pass.
+
+Usually, you can anticipate why a test will fail as it evolves and know when it will pass. If a test passes before I expect, I'm immediately sceptical and will look into why rather than assuming it passed for the right reasons.