diff --git a/core/tests/Drupal/Tests/SkippedDeprecationTest.php b/core/tests/Drupal/Tests/SkippedDeprecationTest.php
index f8028d275a..c6a08254d7 100644
--- a/core/tests/Drupal/Tests/SkippedDeprecationTest.php
+++ b/core/tests/Drupal/Tests/SkippedDeprecationTest.php
@@ -2,8 +2,6 @@
 
 namespace Drupal\Tests;
 
-use PHPUnit\Framework\Error\Warning;
-
 /**
  * @group Test
  */
@@ -35,17 +33,21 @@ public function testSkippingDeprecationsAgain() {
    * @see Drupal\Tests\Traits\PHPUnit8Warnings
    */
   public function testSkippingPhpUnit8Warnings() {
+
+    // Ensure the deprecation helper is enabled regardless of the configured
+    // setting.
     $original_setting = getenv('SYMFONY_DEPRECATIONS_HELPER');
+    putenv('SYMFONY_DEPRECATIONS_HELPER=disabled');
 
     // When the deprecation helper is disabled, both a warning that core fails
     // and a deprecation warning that core passes should be silenced.
-    putenv('SYMFONY_DEPRECATIONS_HELPER=disabled');
-
     $this->addWarning('Warning for \\Drupal\\Tests\\Traits\\PHPUnit8Warnings::$coreFailingWarnings');
     $this->addWarning('Warning for \\Drupal\\Tests\\Traits\\PHPUnit8Warnings::$corePassingDeprecationsWarnings');
-
     $this->addToAssertionCount(1);
+
+    // Restore the configured deprecation handling.
     putenv("SYMFONY_DEPRECATIONS_HELPER=$original_setting");
+
   }
 
   /**
@@ -54,22 +56,19 @@ public function testSkippingPhpUnit8Warnings() {
    * @see Drupal\Tests\Traits\PHPUnit8Warnings
    */
   public function testNotSkippingPhpUnit8Warnings() {
-    $original_setting = getenv('SYMFONY_DEPRECATIONS_HELPER');
 
     // Ensure the deprecation helper is enabled regardless of the configured
     // setting.
+    $original_setting = getenv('SYMFONY_DEPRECATIONS_HELPER');
     putenv('SYMFONY_DEPRECATIONS_HELPER=max[total]=0');
 
     // The warning that core fails should still be silenced.
     $this->addWarning('Warning for \\Drupal\\Tests\\Traits\\PHPUnit8Warnings::$coreFailingWarnings');
-
-    // The warning that core does not fail should be flagged.
-    // @todo This doesn't work.
-    // $this->addWarning('Warning for \\Drupal\\Tests\\Traits\\PHPUnit8Warnings::$corePassingDeprecationsWarnings');
-    // $this->expectException(Warning::class);
     $this->addToAssertionCount(1);
 
+    // Restore the configured deprecation handling.
     putenv("SYMFONY_DEPRECATIONS_HELPER=$original_setting");
+
   }
 
 }