WorldPay payment gateway test account

It has no test account however you can use the LIVE in test mode for testing
http://www.ukbusinessforums.co.uk/forums/showthread.php?t=211474

Magento Extension:
http://www.magentocommerce.com/magento-connect/worldpay-extension.html

Support - Forum:
http://www.magentocommerce.com/boards/viewthread/10803/P150/

Guides:
http://www.worldpay.com/support/kb/bg/pdf/tgl.pdf
http://www.worldpay.com/support/kb/bg/testandgolive/tgl.html