Issue #3228042: Automated Drupal 9 compatibility fixes

Closes #3228042

tests/src/Functional/OnDeleteReferentProtectReferentTest.php

@@ -19,6 +19,11 @@ class OnDeleteReferentProtectReferentTest extends BrowserTestBase {
    */
   public static $modules = ['erg_test'];
 
+  /**
+   * {@inheritdoc}
+   */
+  protected $defaultTheme = 'stark';
+
   /**
    * Tests entity reference deletion.
    */
@@ -36,7 +41,7 @@ class OnDeleteReferentProtectReferentTest extends BrowserTestBase {
     $users = $referee->get('users')->referencedEntities();
     $this->assertSame($user->id(), $users[0]->id());
 
-    $this->setExpectedException(EntityStorageException::class);
+    $this->expectException(EntityStorageException::class);
     $user->delete();
   }