Add Python unit tests to ensure the skip link element is present

wagtail/admin/templates/wagtailadmin/skeleton.html

@@ -32,7 +32,7 @@
 
         {% block js %}{% endblock %}
 
-        <a class="skiplink button" href="#main" data-controller="w-skip-link" data-action="w-skip-link#skip">{% trans 'Skip to main content' %}</a>
+        <a class="skiplink button" href="#main" data-controller="w-focus" data-action="w-focus#focus:prevent">{% trans 'Skip to main content' %}</a>
 
         <div class="wrapper">
             {% block furniture %}{% endblock %}

wagtail/admin/tests/tests.py

@@ -31,6 +31,22 @@ class TestHome(WagtailTestUtils, TestCase):
         self.assertEqual(response.status_code, 200)
         self.assertContains(response, "Test Site")
 
+    def test_accessible_skip_link_exists(self):
+        response = self.client.get(reverse("wagtailadmin_home"))
+        self.assertEqual(response.status_code, 200)
+        soup = self.get_soup(response.content)
+
+        # Check that the skip link is present and has the correct attributes
+        skip_link = soup.select_one(".skiplink")
+        self.assertIsNotNone(skip_link)
+        self.assertEqual(skip_link["href"], "#main")
+        self.assertEqual(skip_link["data-controller"], "w-focus")
+        self.assertEqual(skip_link["data-action"], "w-focus#focus:prevent")
+
+        # Check that the main content area has the correct ID
+        main_content = soup.select_one("#main")
+        self.assertIsNotNone(main_content)
+
     def test_admin_menu(self):
         response = self.client.get(reverse("wagtailadmin_home"))
         self.assertEqual(response.status_code, 200)