Initial Drupal 11 with DDEV setup

web/core/tests/Drupal/Tests/WaitTerminateTestTrait.php

@@ -0,0 +1,24 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests;
+
+/**
+ * Provides a method to enforce that requests will wait for the terminate event.
+ */
+trait WaitTerminateTestTrait {
+
+  /**
+   * Specify that subsequent requests must wait for the terminate event.
+   *
+   * The terminate event is fired after a response is sent to the user agent.
+   * Tests with assertions which operate on data computed during the terminate
+   * event need to enable this.
+   */
+  protected function setWaitForTerminate(): void {
+    $this->setContainerParameter('drupal.test_wait_terminate', TRUE);
+    $this->rebuildContainer();
+  }
+
+}