问PhpUnit没有显示php致命错误的堆栈跟踪

EN

        /**
         * This is for use when you have the UBER-LAME...
         * "PHP Fatal error:  Maximum function nesting level of '100' reached,
         * aborting!  in Lame.php(1273)
         * ...which just craps out leaving you without a stack trace.
         * At the line in the file where it finally spazzes out add
         * something like...
         * DebugUtil::dumpStack('/tmp/lame');
         * It will write the stack into that file every time it passes that
         * point and when it eventually blows up (and probably long before) you
         * will be able to see where the problem really is.
         */
        public static function dumpStack($fileName)
        {
            $stack = "";
            foreach (debug_backtrace() as $trace)
            {
                if (isset($trace['file'])  &&
                    isset($trace['line'])  &&
                    isset($trace['class']) &&
                    isset($trace['function']))
                {
                    $stack .= $trace['file']     . '#' .
                              $trace['line']     . ':' .
                              $trace['class']    . '.' .
                              $trace['function'] . "\n";
                }
            }
            file_put_contents($fileName, $stack);
        }