Our build server failed because of frontend tests. However, all our
fullstack tests are passing... So maybe an issue in our test setup, not
reproducible in a real browser?
This commit:
ee4f132b0f (diff-0806c5f3fdae5e139222967601c7faca)
adds MutationObserver to their test setup. Adding it to our test suites
that touch the `editor` directly fixes our tests, too!
From what I can tell is that prosemirror is calling
`this.observer.takeRecords()`. Probably `tiptap` updated its
dependencies at some point and that's where `this.observer` was
introduced? Hard to tell. It really looks just like an issue only
present in test environments, so I think it's safe not to investigate
any further.
