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.
Using `render :nothing` was deprecated, but we never noticed it because
we didn't have a test for the action using it. In Rails 5.1, it raises
an exception.
Using `head :ok` and adding a test for this scenario solves the issue.
CKEditor repositions the dialog to attach an image after showing it. If
its position changes right when Capybara is trying to click the "Upload"
link, the click does not work properly.
I haven't found a way to check the dialog has stopped moving, so I've
chosen to force its position to the top.
Without this change, this test failed a lot on my machine when using
Rails 5.1, both with an "iframe ckeditor" and an "inline ckeditor".
However, it didn't fail when using Rails 5.0.
We were manually setting `http://www.example.com`. However, Capybara now
uses `http://127.0.0.1`.
While we could change the code to use `127.0.0.1`, I think directly
using `Capybara.app_host` makes it easier to realize what the code is
doing. And, particularly, now it's clear the host has nothing to do with
our `Setting["url"]`, which by default points to `www.example.com` as
well.
