diff --git a/core/modules/block/src/Tests/BlockAdminThemeTest.php b/core/modules/block/src/Tests/BlockAdminThemeTest.php
index bd2edc0..7bcafe8 100644
--- a/core/modules/block/src/Tests/BlockAdminThemeTest.php
+++ b/core/modules/block/src/Tests/BlockAdminThemeTest.php
@@ -43,10 +43,9 @@ function testAdminTheme() {
     $this->drupalGet('admin/structure/block/list/bartik');
     $this->assertResponse(200);
 
-    // Ensure that users without the 'view the administration theme' permission
-    // cannot view the block demonstration page for the admin theme.
+    // Ensure that when access is denied, the default theme is shown instead.
     $this->drupalLogout();
     $this->drupalGet('admin/structure/block/demo/bartik');
-    $this->assertNoRaw('core/themes/bartik');
+    $this->assertRaw('core/themes/classy');
   }
 }