Zend_Mail::setDate PHP Метод

    public function setDate($date = null)
    {
        if ($this->_date === null) {
            if ($date === null) {
                $date = date('r');
            } else {
                if (is_int($date)) {
                    $date = date('r', $date);
                } else {
                    if (is_string($date)) {
                        $date = strtotime($date);
                        if ($date === false || $date < 0) {
                            /**
                             * @see Zend_Mail_Exception
                             */
                            require_once 'Zend/Mail/Exception.php';
                            throw new Zend_Mail_Exception('String representations of Date Header must be ' . 'strtotime()-compatible');
                        }
                        $date = date('r', $date);
                    } else {
                        if ($date instanceof Zend_Date) {
                            $date = $date->get(Zend_Date::RFC_2822);
                        } else {
                            /**
                             * @see Zend_Mail_Exception
                             */
                            require_once 'Zend/Mail/Exception.php';
                            throw new Zend_Mail_Exception(__METHOD__ . ' only accepts UNIX timestamps, Zend_Date objects, ' . ' and strtotime()-compatible strings');
                        }
                    }
                }
            }
            $this->_date = $date;
            $this->_storeHeader('Date', $date);
        } else {
            /**
             * @see Zend_Mail_Exception
             */
            require_once 'Zend/Mail/Exception.php';
            throw new Zend_Mail_Exception('Date Header set twice');
        }
        return $this;
    }

 public function testClearDate()
 {
     $mail = new Zend_Mail();
     $mail->setDate();
     $mail->clearDate();
     $this->assertFalse(isset($mock->headers['Date']));
 }