A good engineer is no good without proper tooling. Sometimes you just can't find any tool that really works for you, so you do what any other good engineer does: you write your own.
Testing for projects with optional dependencies
This is a small Python library for writing tests that depend on optional packages. I needed it for testing my other libraries to make sure they worked in different environments, with different optional packages missing or present. Perhaps I had a bit too much fun giving this library a character...
Shape-aware array type hints for NumPy
Although nowadays I generally use runtime type-checking for testing array shapes, I tried to get static type hints to do the trick when I was first getting started with numerical codebases. They are not super effective, but for certain relatively simple use cases they work pretty well.
Reusable modules for C
These are some modules I kept reusing across C projects for embedded systems. Before you ask, no, there is no good reason to not write tests for critical software. Also, OOP in C is a pretty good idea, although maybe I should not have used so many macros.
Isolated test sessions for TypeScript projects
I'm surprised such a library didn't exist. This library is fully vibe-coded. Although it's not the same quality as a "hand-made" library, I use it in my other projects and it works well. Kids, test your code and don't let AI write the tests for you.
API reference snippets from TypeScript source
Zensical is a relatively new tool for static site generation, so it doesn't yet have a lot of plugins. I wanted to generate automatic API reference documentation from JSDoc comments, but there was no such tool that would work with Zensical. This is also a vibe-coded project, but sometimes good engineering effort is better spent elsewhere. If you're wondering, this library is tested and works pretty well.