Implementation not derived from requirements in Clean Code Applied: We write a Web Server, ep. 5

[Jakub Kaczor]

In the mentioned episode, the authors implement a web server for their video hosting application. As I understand, the implementation should be derived as needed from the requirements and use cases, as was done in the previous episodes of the series. TDD should show what functionality of the web server is truly needed for the application, and verify the initial high level design. Here, it seems not to be the case. The authors just create a module with new classes and start implementing them, without using them first in the main application. Doesn't it conflict with software craftsmanship principles presented in the Clean Code, and the idea of creating a web server themselves, so it is tailored to the application?