Like I mentioned:

``` function setButtonState() { const res = this.fetchSomeResult(); // returns an unfulfilled promise if (res) { return true; }

  return false;

} ```

as a unit test would quickly fail when you want it to. An E2E test would pass, but for the wrong reasons. This has nothing to do with app state, and everything to do with not being scientific, and testing all sorts of variable things at once just because, "that's what the user sees".