code: def test_serve_strict(self, mock_serve):
      result = self.runner.invoke(
          cli.cli, ["serve", "--strict"], catch_exceptions=False
      )
  
      self.assertEqual(result.exit_code, 0)
      mock_serve.assert_called_once_with(
          dev_addr=None,
          open_in_browser=False,
          livereload=True,
          build_type=None,
          config_file=None,
          strict=True,
          theme=None,
          use_directory_urls=None,
          watch_theme=False,
          watch=(),
      )
  
imports: import io
  import logging
  import unittest
  from unittest import mock
  from click.testing import CliRunner
  from mkdocs import __main__
label_desc: Use image node_id 5 for calling the CLITests obj's underlying member method code with example usage: obj.test_serve_strict(mock_serve) without return types