A test server is now online at test.cardfortress.com.
You can download the Business::OnlinePayment::CardFortress perl client which talks to it.
You can test with Freeside 2.1.0 or later. Turn on the business-onlinepayment-test_transaction config flag, put private_key.txt in /usr/local/etc/freeside/, and set the business-onlinepayment config option as follows:
Freeside users with a current support contract are invited to join our beta testing program.