code: def test_nav_from_files(self):
      expected = dedent(
          """
              Page(title=[blank], url='/')
              Page(title=[blank], url='/about/')
              """
      )
      cfg = load_config(site_url="http://example.com/")
      fs = [
          File(
              "index.md",
              cfg.docs_dir,
              cfg.site_dir,
              cfg.use_directory_urls,
          ),
          File(
              "about.md",
              cfg.docs_dir,
              cfg.site_dir,
              cfg.use_directory_urls,
          ),
      ]
      files = Files(fs)
      site_navigation = get_navigation(files, cfg)
      self.assertEqual(str(site_navigation).strip(), expected)
      self.assertEqual(len(site_navigation.items), 2)
      self.assertEqual(len(site_navigation.pages), 2)
      self.assertEqual(
          repr(site_navigation.homepage), "Page(title=[blank], url='/')"
      )
  
imports: import sys
  import unittest
  from mkdocs.structure.files import File, Files, set_exclusions
  from mkdocs.structure.nav import Section, _get_by_type, get_navigation
  from mkdocs.structure.pages import Page
  from mkdocs.tests.base import dedent, load_config
label_desc: Use image node_id 12 for calling the SiteNavigationTests obj's underlying member method code with example usage: obj.test_nav_from_files() without return types