I'm working on a large solo game project where I am attempting to use a combination of traditional DOM elements (React) and canvas elements (PixiJS and react-pixi-fiber) in the project. I wanted to gain visibility into the canvas element in a functional test, and didn't immediately see any libraries or posts explaining how this could be done. I've come up with a process that works for me, using Cypress, and wrote about it. Perhaps someone gets some value from this, and I'm happy to discuss testing and PixiJS! Thanks!
https://medium.com/@zenblender/functional-testing-of-a-hybrid-pixijs-react-app-281ed5ea04b3