'``deployment_from_configuration`` raises a ``ConfigurationError`` if
the deployment_configuration refers to a non-existent IP.'

def test_error_on_unknown_ip(self):

    exception = self.assertRaises(ConfigurationError, deployment_from_configuration, DeploymentState(), dict(version=1, nodes={u'1.2.3.4': []}), {})
    self.assertEqual(u'No    known    node    with    address    1.2.3.4.', exception.message)
