This is a mistake I made in commit f2ef27d3. Back then I thought we
needed to keep Globalize.locale and I18n.locale in sync, but the truth
is it automatically happens when setting Globalize.locale to nil.
So now we can use I18n.with_locale (at least in the tests) and forget
about Globalize, which will make it easier to switch to Mobility in the
future.
This code might be slightly slower because it performs one query per
field in the form, but I didn't notice any differences on my development
machine, and the code is now much easier to understand.
Since we've recently added German to the available languages, and we
might support every language in the future, we're using the fictional
world language to check a locale which isn't available.
Another option could be to set the available locales in the test
environment (or the rspec helper), but then we'd have to make sure it's
executed before the call to `globalize_accessors` in the model, and it
might be confusing for developers.
In order to be consistent with similar specs, the I18nContent#begins_with_key
spec was improved by explicitly specifying an I18n key for one (1) factory
that relied on its default value
