Refs #27804 -- Used subTest() in HTMLEqualTests.test_self_closing_tags.

tests/test_utils/tests.py

@@ -542,6 +542,7 @@ class HTMLEqualTests(SimpleTestCase):
             'base', 'col',
         )
         for tag in self_closing_tags:
+            with self.subTest(tag):
                 dom = parse_html('<p>Hello <%s> world</p>' % tag)
                 self.assertEqual(len(dom.children), 3)
                 self.assertEqual(dom[0], 'Hello')