def test_missing_environment(self):
        options = BenchmarkOptions()
        options.parseOptions([])
        with capture_stderr() as captured_stderr:
            exception = self.assertRaises(
                SystemExit,
                get_cluster, options, {},
            )
            self.assertIn('not set', exception.args[0])
            self.assertIn(options.getUsage(), captured_stderr())
If no cluster option and no environment, script fails
dataset/ETHPy150Open ClusterHQ/flocker/benchmark/test/test_script.py/ClusterConfigurationTests.test_missing_environment