Reminds me of a little vscode extension I wrote for myself to integrate ChatGPT into my projects. I didn't do a great job with documentation, but you can reference other files within comments to send them as context. So something like

/* Write tests for [xyz/(./xyz.ts) using [abc tests](./abc.spec.ts) as an example to reference

@ChatGPT */

Reference: https://github.com/CapsuleCat/sora-by-capsule-cat

I'll have to check out how your version pulls in the project as context.