Want to know how to write tests for your Existing Code?

Hi Curious People!
Do you _want_ to know how to write tests for your **_existing code**_?
Drop us a comment below so we know this is something you are interested in. :+1:

The issue names no files, tests, or entry points and only asks whether readers want guidance on testing existing code. Review the single comment and the book’s existing testing material first; done would require an agreed scope and a documented guide.

Written by the indexing model from the issue text.