src/Peach/Http/Header/CookieExpiresFormat.php
private function formatWeekday($day)
    {
        $weekdayList = $this->getWeekdayMapping();
        if (array_key_exists($day, $weekdayList)) {
            return $weekdayList[$day];
        }
        // @codeCoverageIgnoreStart
        throw new Exception("Invalid day: {$day}");
        // @codeCoverageIgnoreEnd
    }
private function formatWeekday($day)
    {
        $weekdayList = $this->getWeekdayMapping();
        if (array_key_exists($day, $weekdayList)) {
            return $weekdayList[$day];
        }
        // @codeCoverageIgnoreStart
        throw new Exception("Invalid day: {$day}");
        // @codeCoverageIgnoreEnd
    }
指定された曜日を
"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
のいずれかに変換します.

@param  int $day 曜日 (0 以上 6 以下)
@return string   指定された曜日に対応する文字列