Mage_Core_Model_Resource_Session::getLifeTime PHP Method

    public function getLifeTime()
    {
        if (is_null($this->_lifeTime)) {
            $configNode = Mage::app()->getStore()->isAdmin() ? 'admin/security/session_cookie_lifetime' : 'web/cookie/cookie_lifetime';
            $this->_lifeTime = (int) Mage::getStoreConfig($configNode);
            if ($this->_lifeTime < 60) {
                $this->_lifeTime = ini_get('session.gc_maxlifetime');
            }
            if ($this->_lifeTime < 60) {
                $this->_lifeTime = 3600;
                //one hour
            }
            if ($this->_lifeTime > self::SEESION_MAX_COOKIE_LIFETIME) {
                $this->_lifeTime = self::SEESION_MAX_COOKIE_LIFETIME;
                // 100 years
            }
        }
        return $this->_lifeTime;
    }

 public function testGetLifeTime()
 {
     $this->assertGreaterThan(0, $this->_model->getLifeTime());
 }