'``Configuration.applications`` raises a
``ConfigurationError`` if the application_configuration has a link
entry that has extra keys.'

def test_links_extra_keys(self):

    config = dict(version=1, applications={u'mysql-hybridcluster': dict(image=u'busybox', links=[{u'remote_port': 90, u'local_port': 40, u'alias': u'other', u'foo': 5, u'bar': u'six'}])})
    parser = FlockerConfiguration(config)
    exception = self.assertRaises(ConfigurationError, parser.applications)
    self.assertEqual(u"Application    'mysql-hybridcluster'    has    a    config    error.    Invalid    links    specification.    Unrecognised    keys:    bar,    foo.", exception.message)
