This is the first time I've read an AI-heavy piece and stayed engaged with it all the way through. I think the author's sharing the prompts was key to that experience.
Writing unit tests is futile exercise without a specification.
The software under test is always modeling something -- business logic, a communications protocol, a control algorithm, a standard, etc. Behind each of those things is a specification. If a specification doesn't exist then the software is called a prototype. For sustained long term incremental development a specification must exist.
The purpose of unit tests is to assert specification-defined invariants at the module interface level.
Unit tests are durable iff the specification they uphold is explicit and accessible to developers and the scope of the test is small. It's futile to write good tests for a module which has ambiguous utility.
priors: I worked in embedded SW and am now a PhD student.
I found the linked article to be difficult to follow. Vacliv Smil wrote a book called Energy and Civilization (2017) in which he argues that the ability to harness energy is what makes civilizations thrive and enables the production of culture.