.../tests/src/Kernel/CKEditor5PluginManagerTest.php     | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/core/modules/ckeditor5/tests/src/Kernel/CKEditor5PluginManagerTest.php b/core/modules/ckeditor5/tests/src/Kernel/CKEditor5PluginManagerTest.php
index 9b8742b57c..745a2c0f3e 100644
--- a/core/modules/ckeditor5/tests/src/Kernel/CKEditor5PluginManagerTest.php
+++ b/core/modules/ckeditor5/tests/src/Kernel/CKEditor5PluginManagerTest.php
@@ -82,6 +82,16 @@ protected function setUp(): void {
     $this->typedConfig = $this->container->get('config.typed');
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  protected function enableModules(array $modules) {
+    parent::enableModules($modules);
+    // Ensure the CKEditor 5 plugin manager instance on the test reflects the
+    // status after the module is installed.
+    $this->manager = $this->container->get('plugin.manager.ckeditor5.plugin');
+  }
+
   /**
    * Mocks a module providing a CKEditor 5 plugin in VFS.
    *
@@ -1372,8 +1382,11 @@ public function providerTestProvidedElements(): array {
           'ckeditor5_plugin_elements_test_headingCombo',
           'ckeditor5_paragraph',
         ],
-        'text_editor_settings' => [
-          'plugins' => [],
+        'text_editor_settings' => ['plugins' => [],
+          // Deviate from the default toolbar items because that would cause
+          // the `ckeditor5_heading` plugin to be enabled.
+          // @see \Drupal\ckeditor5\Plugin\Editor\CKEditor5::getDefaultSettings()
+          'toolbar' => ['items' => ['bold', 'italic']],
         ],
         'expected_elements' => [
           'p' => [