diff --git a/tests/phpunit/tests/mail.php b/tests/phpunit/tests/mail.php
index 25c49c1c84..120147cfc5 100644
--- a/tests/phpunit/tests/mail.php
+++ b/tests/phpunit/tests/mail.php
@@ -9,6 +9,11 @@ class Tests_Mail extends WP_UnitTestCase {
 		unset( $GLOBALS['phpmailer']->mock_sent );
 	}
 
+	function tearDown() {
+		unset( $GLOBALS['phpmailer']->mock_sent );
+		parent::tearDown();
+	}
+
 	/**
 	 * Send a mail with a 1000 char long line.
 	 *