code: def test_subcommand_help(self):
      with testing_utils.capture_output() as output:
          with self.assertRaises(SystemExit):
              script.superscript_main(args=["test_script", "foo"])
              assert "parlai test_script" in output.getvalue()
              assert "--foo" in output.getvalue()
  
imports: import sys
  import unittest
  from unittest.mock import patch
  from parlai.core.params import ParlaiParser
  import parlai.core.script
  import parlai.utils.testing
label_desc: Use image node_id 5 for calling the TestSuperCommand obj's underlying member method code with example usage: obj.test_subcommand_help() without return types