This book talks about unit tests, but for UI they are mostly useless. I found that for UI the most essential refactoring tools are storybook and visual diff tests.

I remember the time when we had to delete “a lot” of UI tests because the implementation and the framework deprecated and we had to move forward (usual stuff, eg vulnerabilities). Refactoring all of those tests would require a bunch of effort therefore we stopped adding new features and just waited for the last customer subscription to expire, then we moved to other more important stuff.