Some specs involving CKEditor were failing sometimes in the Rails 5.1
branch. The reason why these specs pass with Rails 5.0 but fail with
Rails 5.1 are unknown. On my machine the tests pass when precompiling
the assets, which makes me think it's related to the way Rails handles
them, but it might have nothing to do with it.
The only (apparently) 100% reliable solution I've found is to wait for
CKEditor to load before trying to fill it in. After running the tests on
my machine hundreds of time, I didn't get a single failure.
5b97b20f96