Catching two accessibility issues along the way: we were putting the wrong accessible labels on the 'expand' button, and even the off-screen pages of the spotlight tile were being exposed to accessibility technologies rather than hidden.
This was the result of me playing around with RxJS marble testing to understand how to get things done with its TestScheduler. I discovered that it lacks a clear way to fire arbitrary actions during the test, so I built a small helper function called schedule which does this for us.
