code: def test_missing_required(self):
      conf = defaults.MkDocsConfig()
  
      errors, warnings = conf.validate()
  
      self.assertEqual(
          errors,
          [
              (
                  "site_name",
                  ValidationError(
                      "Required configuration not provided."
                  ),
              )
          ],
      )
      self.assertEqual(warnings, [])
  
imports: import os
  import unittest
  from mkdocs import exceptions
  from mkdocs.config import base
  from mkdocs.config import config_options
  from mkdocs.config import defaults
  from mkdocs.config.base import ValidationError
  from mkdocs.tests.base import change_dir, tempdir
label_desc: Use image node_id 2 for calling the ConfigBaseTests obj's underlying member method code with example usage: obj.test_missing_required() without return types