OPENEUROPA-2020: Ensure there is a preview for embed media in WYSIWYG.

modules/oe_media_embed/css/ckeditor_embed.css

@@ -0,0 +1,8 @@
+[data-oembed] {
+    height: 8em;
+    width: 100%;
+    background-color: #E0E0E0;
+    text-align: center;
+    padding-bottom: 1.2em;
+    line-height: 8em;
+}

modules/oe_media_embed/js/plugins/embed_media/plugin.js

@@ -67,8 +67,22 @@
 
         // Fetch the rendered entity.
         init: function () {
-          // @todo fetch the rendered tag once we actually have a filter in
-          // place.
+          /** @type {CKEDITOR.dom.element} */
+          // @todo: Use this code once we need to render the media with a defined display mode in WYSIWYG.
+          /**var element = this.element;
+          // Use the Ajax framework to fetch the HTML, so that we can retrieve
+          // out-of-band assets (JS, CSS...).
+          var entityEmbedPreview = Drupal.ajax({
+            base: element.getId(),
+            element: element.$,
+            url: Drupal.url('embed/preview/' + editor.config.drupal.format + '?' + $.param({
+              value: element.getOuterHtml()
+            })),
+            progress: {type: 'none'},
+            // Use a custom event to trigger the call.
+            event: 'entity_embed_dummy_event'
+          });
+          entityEmbedPreview.execute();*/
         },
 
         // Downcast the element.

modules/oe_media_embed/oe_media_embed.module

@@ -0,0 +1,15 @@
+<?php
+
+/**
+ * @file
+ * OpenEuropa Media Embed module.
+ */
+
+declare(strict_types = 1);
+
+/**
+ * Implements hook_ckeditor_css_alter().
+ */
+function oe_media_embed_ckeditor_css_alter(&$css, $editor) {
+  $css[] = drupal_get_path('module', 'oe_media_embed') . '/css/ckeditor_embed.css';
+}

modules/oe_media_embed/tests/FunctionalJavascript/CKEditorIntegrationTest.php

@@ -122,6 +122,7 @@ public function testIntegration(): void {
     // Verify that the embedded entity gets a preview inside the text editor.
     $this->getSession()->switchToIFrame('ckeditor');
     $this->assertSession()->pageTextContains('My image media');
+    $this->assertSession()->pageTextContains('Digital Single Market: cheaper calls to other EU countries as of 15 May');
     $this->getSession()->switchToIFrame();
     $this->getSession()
       ->getPage()