Shopify/active_merchant — pull request #1491 by kikito (2014-12-12 17:03:36+00:00)
Title: Null gateway

Related with #1489

A Null object never fails, and returns "safe" values with no side-effects.

In this case I think it was fine returning "real" responses instead of creating a "NullResponse" object, since responses are treated as "data" - they don't change the state of anything by themselves.