Back to back testing is a technique in which two or more variant of a component are tested with the same inputs. After that, the outputs are functionally compared and analyzed to find out the functional or non-functional disorder which may occur in future. This type of testing involves a cross-comparison of overall responses which are obtained from functional software components. And, whenever a defect or any discrepancy is found, that should be corrected in a defined time.
The best example to illustrate back to back methodology is ATM machine. The software used in the ATM works on same technique, it produces same with the same number of inputs, without knowing and understanding that how the data could be examined and executed at the background.
It also includes testing of different versions of an application, used in POS machine (Point of sales – card swipe machine). At this time, the responses should be same across all the versions with the same number of inputs. Backend process of data manipulation is not a matter of consideration, here.
Generally, Back to Back testing involves following steps: