'The all option also shows settings with the default value.'

def test_all(self):

    self.write_settings(u'settings_to_diff.py', sdict={u'STATIC_URL': u'None'})
    self.addCleanup(self.remove_settings, u'settings_to_diff.py')
    args = [u'diffsettings', u'--settings=settings_to_diff', u'--all']
    (out, err) = self.run_manage(args)
    self.assertNoOutput(err)
    self.assertOutput(out, u'###    STATIC_URL    =    None')
