Country tests.

  >>> from plone.app.i18n.locales.interfaces import ICountries
  >>> from zope.component import queryUtility

  >>> util = queryUtility(ICountries)
  >>> util
  <Countries at ...>

  >>> countrycodes = util.getAvailableCountries()
  >>> len(countrycodes)
  1

  >>> u'en' in countrycodes
  True

  >>> id(countrycodes) == id(util.countries)
  False

  >>> countries = util.getCountries()
  >>> len(countries) > 200
  True

  >>> de = countries[u'de']
  >>> de[u'name']
  u'Germany'

  >>> de[u'flag']
  u'/++resource++country-flags/de.gif'

  >>> old = util.getAvailableCountries()
  >>> countries = ['de']
  >>> util.setAvailableCountries(countries)

  >>> util.getAvailableCountries()
  ['de']

  >>> id(countries) == util.countries
  False

  >>> util.setAvailableCountries(old)