Shopify/active_merchant — pull request #433 by mipearson (2012-08-09 00:58:37+00:00)
Title: Only consider the last number in the CC or reference in BogusGateway.

BogusGateway only allowing CC numbers like '1' and '2' makes mixing BogusGateway & CC form validation routines very difficult.

To work around this I've modified BogusGateway to use the last digit of the CC (or reference) to determine whether the transaction has failed.