code: def test_fd_command_line_interface_folder(self):
      runner = CliRunner()
      image_file = os.path.join(
          os.path.dirname(__file__), "test_images"
      )
  
      result = runner.invoke(face_detection_cli.main, args=[image_file])
      self.assertEqual(result.exit_code, 0)
      self.assertTrue("obama_partial_face2.jpg" in result.output)
      self.assertTrue("obama.jpg" in result.output)
      self.assertTrue("obama2.jpg" in result.output)
      self.assertTrue("obama3.jpg" in result.output)
      self.assertTrue("biden.jpg" in result.output)
  
imports: import unittest
  import os
  import numpy
  from click.testing import CliRunner
  from face_recognition import api
  from face_recognition import face_recognition_cli
  from face_recognition import face_detection_cli
label_desc: Use image node_id 28 for calling the Test_face_recognition obj's underlying member method code with example usage: obj.test_fd_command_line_interface_folder() without return types