Issue #2930274 by dawehner, Berdir, slashrsm, Sam152: View mode class is not...

Issue #2930274 by dawehner, Berdir, slashrsm, Sam152: View mode class is not built correctly in media.html.twig

core/modules/media/tests/src/Functional/MediaUiFunctionalTest.php

@@ -173,6 +173,7 @@ public function testMediaWithMultipleMediaTypes() {
     $this->drupalGet('media/' . $first_media_item->id());
     $assert_session->statusCodeEquals(200);
     $assert_session->pageTextContains($first_media_item->getName());
+    $assert_session->elementsCount('css', '.media--view-mode-full', 1);
 
     // Go to second media item.
     $this->drupalGet('media/' . $second_media_item->id());

core/themes/classy/templates/content/media.html.twig

@@ -17,7 +17,7 @@
     'media',
     'media--type-' ~ media.bundle()|clean_class,
     not media.isPublished() ? 'media--unpublished',
-    view_mode ? 'media--view-mode-' ~ view_mode.id()|clean_class,
+    view_mode ? 'media--view-mode-' ~ view_mode|clean_class,
   ]
 %}
 <article{{ attributes.addClass(classes) }}>