My work in T218345: Investigate Selenium tests for validating event logging data looked promising locally until it was time to make the tests pass in CI. I've since discovered that the issue documented in T150435#3479616 is going to block further progress. I need Parsoid in Quibble so that my Selenium tests which exercise actions that happen in a VisualEditor context can run.
Looking at quibble/cmd.py#execute, perhaps after with quibble.backend.ChromeWebDriver(display=display): we could also start a Parsoid service? From setting this up locally, I think all we'd need to do is clone the parsoid repo, have a minimal config (~12 lines), and npm run start.