Fault Injection Testing is an age-old testing technique to understand how a system behaves when it is stressed in unusual ways. Nearly half a century back, it all started with simulating failures in hardware. However later, Industries also started thinking about fault injection testing in software, though not exactly called that way. It was performed as part of "Robustness testing" and "stress testing". Even the DO-178B SW Safety Standard for Aviation does not have the term "fault injection testing". ISO26262 has made an attempt to explicitly define what this type of testing means and has provided guidelines on when and how to perform it. In this article, we have explained what the goal of fault injection testing is and what is the expectation of the ISO26262 Standard on this topic. Further, we have defined (in our own words) a "Systematic approach" to do Fault Injection tests in Software, so as to maximize its effectiveness. Before we go into f...