This blog contains some semantics about Vite I discovered during development of this website.
Vitest Config
Using vitest, you should use the same vite.config and not create a new test config - link.
Otherwise, the version of React used in testing won't match.
In this case, I kept getting the error that React wasn't defined which indicated that I was using an outdated version of React where it was mandatory to import React.
Documentation
This is just a link of some important documentation about assertions.