'Rejects configuration if control node is invalid.'

def test_environment_invalid_control_node(self):

    options = BenchmarkOptions()
    options.parseOptions([])
    self.environ['FLOCKER_ACCEPTANCE_CONTROL_NODE'] = 'notanipaddress'
    with capture_stderr() as captured_stderr:
        exception = self.assertRaises(SystemExit, get_cluster, options, self.environ)
        self.assertIn('notanipaddress', exception.args[0])
        self.assertIn(options.getUsage(), captured_stderr())
