diff -u b/core/modules/layout_builder/tests/src/Unit/BlockComponentRenderArrayTest.php b/core/modules/layout_builder/tests/src/Unit/BlockComponentRenderArrayTest.php
--- b/core/modules/layout_builder/tests/src/Unit/BlockComponentRenderArrayTest.php
+++ b/core/modules/layout_builder/tests/src/Unit/BlockComponentRenderArrayTest.php
@@ -121,6 +121,7 @@
       '#derivative_plugin_id' => NULL,
       'content' => $block_content,
       '#in_preview' => FALSE,
+      '#attributes' => Array (),
     ];
 
     $expected_build_with_expected_cache = $expected_build + [
@@ -198,6 +199,7 @@
       'content' => $block_content,
       '#attributes' => [],
       '#in_preview' => FALSE,
+      '#attributes' => Array (),
     ];
 
     $expected_cache = $expected_build + [