Issue #3281438 by tinto, deviantintegral, catch: Update CKEditorTest to not use Bartik and Seven

(cherry picked from commit 2ba27576)

core/modules/ckeditor/tests/src/Kernel/CKEditorTest.php

@@ -280,14 +280,15 @@ public function testBuildContentsCssJSSetting() {
     $expected[] = $this->fileUrlGenerator->generateString($this->getModulePath('ckeditor_test') . '/css/llama.css') . $query_string;
     $this->assertSame($expected, $this->ckeditor->buildContentsCssJSSetting($editor), '"contentsCss" configuration part of JS settings built correctly while a CKEditorPluginInterface implementation exists.');
 
-    // Enable the Bartik theme, which specifies a CKEditor stylesheet.
-    \Drupal::service('theme_installer')->install(['bartik']);
-    $this->config('system.theme')->set('default', 'bartik')->save();
-    $expected[] = $this->fileUrlGenerator->generateString('core/themes/bartik/css/base/elements.css') . $query_string;
-    $expected[] = $this->fileUrlGenerator->generateString('core/themes/bartik/css/components/captions.css') . $query_string;
-    $expected[] = $this->fileUrlGenerator->generateString('core/themes/bartik/css/components/table.css') . $query_string;
-    $expected[] = $this->fileUrlGenerator->generateString('core/themes/bartik/css/components/text-formatted.css') . $query_string;
-    $expected[] = $this->fileUrlGenerator->generateString('core/themes/bartik/css/classy/components/media-embed-error.css') . $query_string;
+    // Enable the Olivero theme, which specifies a CKEditor stylesheet.
+    \Drupal::service('theme_installer')->install(['olivero']);
+    $this->config('system.theme')->set('default', 'olivero')->save();
+    $expected[] = $this->fileUrlGenerator->generateString('core/themes/olivero/css/base/fonts.css') . $query_string;
+    $expected[] = $this->fileUrlGenerator->generateString('core/themes/olivero/css/base/base.css') . $query_string;
+    $expected[] = $this->fileUrlGenerator->generateString('core/themes/olivero/css/components/embedded-media.css') . $query_string;
+    $expected[] = $this->fileUrlGenerator->generateString('core/themes/olivero/css/components/table.css') . $query_string;
+    $expected[] = $this->fileUrlGenerator->generateString('core/themes/olivero/css/components/text-content.css') . $query_string;
+    $expected[] = $this->fileUrlGenerator->generateString('core/themes/olivero/css/theme/ckeditor-frame.css') . $query_string;
     $this->assertSame($expected, $this->ckeditor->buildContentsCssJSSetting($editor), '"contentsCss" configuration part of JS settings built correctly while a theme providing a CKEditor stylesheet exists.');
   }