'Rejects configuration if hostname mapping is invalid.'

def test_environment_hostname_mapping_not_object(self):

    options = BenchmarkOptions()
    options.parseOptions([])
    self.environ['FLOCKER_ACCEPTANCE_HOSTNAME_TO_PUBLIC_ADDRESS'] = '[{"notanipaddress":    "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())
