Check on mailing_spool too

tests/phpunit/CiviTest/CiviUnitTestCase.php

@@ -391,7 +391,7 @@ protected function setUp(): void {
     // something changed it and then inadvertently didn't restore it.
     $this->errorHandlerAtStartOfTest = set_error_handler(function($errno, $errstr, $errfile, $errline) {});
     restore_error_handler();
-    foreach (['civicrm_option_value', 'civicrm_campaign', 'civicrm_line_item', 'civicrm_im', 'civicrm_address'] as $entity) {
+    foreach (['civicrm_option_value', 'civicrm_campaign', 'civicrm_mailing_spool', 'civicrm_line_item', 'civicrm_im', 'civicrm_address'] as $entity) {
       $this->entityTracking[$entity] = \CRM_Core_DAO::singleValueQuery('SELECT count(*) FROM ' . $entity);
     }
   }
@@ -603,6 +603,9 @@ protected function tearDown(): void {
       if ($entity === 'civicrm_line_item') {
         $field = 'line_total';
       }
+      if ($entity === 'civicrm_mailing_spool') {
+        $field = 'recipient_email';
+      }
       $this->assertEquals($count, \CRM_Core_DAO::singleValueQuery('SELECT count(*) FROM ' . $entity), $entity . ' has not cleaned up well ' . CRM_Core_DAO::singleValueQuery('SELECT ' . $field . ' FROM ' . $entity . ' ORDER BY id DESC LIMIT 1'));
     }
     parent::tearDown();