Eric Volkernick
--- a/core/modules/views/tests/src/Functional/Plugin/ExposedFormTest.php
+++ b/core/modules/views/tests/src/Functional/Plugin/ExposedFormTest.php
+     $this->fail(new FormattableMarkup('The page @url contains no HTML IDs.', $args));
+     return;
+   }
+
+   $message = new FormattableMarkup('The page @url contains duplicate HTML IDs', $args);
+
+   $seen_ids = [];
+   foreach ($elements as $element) {
+     $id = $element->getAttribute('id');
+     if (isset($seen_ids[$id])) {
+       $this->fail($message);
+       return;
+     }
+     $seen_ids[$id] = TRUE;
+   }
+   $this->assertTrue(TRUE, $message);