tests/src/Unit/Render/Placeholder/BigPipeStrategyTest.php | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tests/src/Unit/Render/Placeholder/BigPipeStrategyTest.php b/tests/src/Unit/Render/Placeholder/BigPipeStrategyTest.php
index 8409bc7..34a8bd4 100644
--- a/tests/src/Unit/Render/Placeholder/BigPipeStrategyTest.php
+++ b/tests/src/Unit/Render/Placeholder/BigPipeStrategyTest.php
@@ -43,6 +43,9 @@ class BigPipeStrategyTest extends UnitTestCase {
     $big_pipe_strategy = new BigPipeStrategy($session_configuration->reveal(), $request_stack->reveal());
     $processed_placeholders = $big_pipe_strategy->processPlaceholders($placeholders);
     $this->assertSame($expected_big_pipe_placeholders, $processed_placeholders);
+    if ($request_has_session) {
+      $this->assertSameSize($placeholders, $processed_placeholders, 'BigPipe is able to deliver all placeholders.');
+    }
   }
 
   public function placeholdersProvider() {