diff --git a/test/classes/PMA_Message_test.php b/test/classes/PMA_Message_test.php
index 19db79edfd5a..444b45f5746a 100644
--- a/test/classes/PMA_Message_test.php
+++ b/test/classes/PMA_Message_test.php
@@ -329,6 +329,7 @@ public function testDecodeBB($actual, $expected)
         $GLOBALS['lang'] = 'en';
         $_SESSION[' PMA_token '] = 'token';
         unset($GLOBALS['server']);
+        unset($GLOBALS['collation_connection']);
         $this->assertEquals($expected, PMA_Message::decodeBB($actual));
     }