code: def do_test_stream_command_output(
      self,
      command,
      capture_stdout,
      capture_stderr,
      prefix_output_with_timestamp,
  ):
      stdout = io.StringIO()
      stderr = io.StringIO()
  
      key = secret.make_secret_key()
      service = BasicTaskService(
          "test service", 0, key, nics=None, verbose=2
      )
      try:
          client = BasicTaskClient(
              "test service",
              service.addresses(),
              key,
              verbose=2,
              attempts=1,
          )
          stdout_t, stderr_t = client.stream_command_output(
              stdout, stderr
          )
          client.run_command(
              command,
              {},
              capture_stdout=capture_stdout,
              capture_stderr=capture_stderr,
              prefix_output_with_timestamp=prefix_output_with_timestamp,
          )
          client.wait_for_command_termination(delay=0.2)
          self.assertEqual((True, 0), client.command_result())
  
          if stdout_t is not None:
              stdout_t.join(1.0)
              self.assertEqual(False, stdout_t.is_alive())
          if stderr_t is not None:
              stderr_t.join(1.0)
              self.assertEqual(False, stderr_t.is_alive())
      finally:
          service.shutdown()
  
      stdout = stdout.getvalue()
      stderr = stderr.getvalue()
  
      # remove timestamps from each line in outputs
      if prefix_output_with_timestamp:
          stdout_no_ts = re.sub(
              "^[^[]+", "", stdout, flags=re.MULTILINE
          )
          stderr_no_ts = re.sub(
              "^[^[]+", "", stderr, flags=re.MULTILINE
          )
          # test we are removing something (hopefully timestamps)
          if capture_stdout:
              self.assertNotEqual(stdout_no_ts, stdout)
          if capture_stderr:
              self.assertNotEqual(stderr_no_ts, stderr)
          stdout = stdout_no_ts
          stderr = stderr_no_ts
  
      # remove prefix
      stdout_no_prefix = re.sub(
          "\[0\]<stdout>:", "", stdout, flags=re.MULTILINE
      )
      stderr_no_prefix = re.sub(
          "\[0\]<stderr>:", "", stderr, flags=re.MULTILINE
      )
      # test we are removing something (hopefully prefixes)
      if capture_stdout:
          self.assertNotEqual(stdout_no_prefix, stdout)
      if capture_stderr:
          self.assertNotEqual(stderr_no_prefix, stderr)
      stdout = stdout_no_prefix
      stderr = stderr_no_prefix
  
      if capture_stdout and capture_stderr:
          # both streams should be equal
          self.assertEqual(stdout, stderr)
  
      # streams should have meaningful number of lines and characters
      if capture_stdout:
          self.assertTrue(len(stdout) > 1024)
          self.assertTrue(len(stdout.splitlines()) > 10)
      if capture_stderr:
          self.assertTrue(len(stderr) > 1024)
          self.assertTrue(len(stderr.splitlines()) > 10)
  
imports: import io
  import re
  import unittest
  from horovod.runner.common.service.task_service import BasicTaskService, BasicTaskClient
  from horovod.runner.common.util import secret
label_desc: Use image node_id 8 for calling the TaskServiceTest obj's underlying member method code with example usage: obj.do_test_stream_command_output(command, capture_stdout, capture_stderr, prefix_output_with_timestamp) without return types