Test fakes are still a kind of white-box testing. They are built right into the code of the application and re-use the types that you define within. The kind of integration tests defined in the blog post are, in my opinion, are the most black-box kind of approach you can have. And as such, they are a great way of testing APIs that have many external clients since you are validating it as if you were one. You only look at HTTP, you don't look at how it is implemented.
frankly not the easiest to follow I would love to know more about this. As you can see in my blog, I'm not a very frequent writer, if you have concrete feedback I can use to write better and make blog posts that are easier to follow that would help me tremendously.
LLM? No. I wrote every word myself, even the mistakes. I based it on something I built for the company I'm currently working at.