diff --git a/core/tests/Drupal/Tests/Component/Datetime/DateTimePlusTest.php b/core/tests/Drupal/Tests/Component/Datetime/DateTimePlusTest.php
index 5e312a1..6e5a956 100644
--- a/core/tests/Drupal/Tests/Component/Datetime/DateTimePlusTest.php
+++ b/core/tests/Drupal/Tests/Component/Datetime/DateTimePlusTest.php
@@ -716,6 +716,17 @@ function providerTestSerialization() {
           'langcode' => NULL,
         ],
       ],
+      [
+        DateTimePlus::createFromFormat('Y-m-d H:i:s', '2000-01-01 00:00:00', new \DateTimeZone('America/Los_Angeles')),
+        [
+          'datetime' => [
+            'date' => '2000-01-01 00:00:00.000000',
+            'timezone_type' => 3,
+            'timezone' => 'America/Los_Angeles',
+          ],
+          'langcode' => NULL,
+        ],
+      ]
     ];
   }