Add tests for MountGetters
Created by: felixfbecker
Adds generic tests that test invariants of all mount getters.
Updates GitHub DOM fixtures to incorporate DOM changes (new tests were failing against old fixtures).
I had to add a custom jest-environment to both use latest JSDOM (for el.insertAdjacentElement()
) and expose jsdom
as a global.
This also allowed me to get rid of the MutationObserver
polyfill (and the IntersectionObserver
wasn't used anymore).
This increases the browser extension test coverage from 36.06% to 41.20%