Why this change?
Returning an array makes it hard to immediately retrieve a setting by
name and makes the retrieval an O(N) operation. By returning an array,
we make it easier for us to lookup a setting by name and retrieval is
O(1) as well.
When a theme setting of type `upload` has a default upload, it should return the URL of the specified default upload until a custom upload is used for the setting. However, currently this isn't the case and we get null instead of the default upload URL.
The reason for this is because the `super` method of `#value` already returns the default upload URL (if there's one), so we can't pass that to `cdn_url` which expects an upload ID:
c961dcc757/lib/theme_settings_manager.rb (L212)
This commit fixes the bug by skipping the call to `cdn_url` when we fallback to the default upload for the setting value.
It's very easy to forget to add `require 'rails_helper'` at the top of every core/plugin spec file, and omissions can cause some very confusing/sporadic errors.
By setting this flag in `.rspec`, we can remove the need for `require 'rails_helper'` entirely.
