DB::debugMode PHP Method

    public static function debugMode($handler = true)
    {
        DB::$success_handler = $handler;
    }

 function test_3_debugmode_handler()
 {
     global $debug_callback_worked;
     DB::debugMode('my_debug_handler');
     DB::query("SELECT * FROM accounts WHERE username!=%s", "Charlie's Friend");
     $this->assert($debug_callback_worked === 1);
     DB::debugMode(false);
 }