Shift Left
A typical software development process is sequential (1970s-1990s): define requirements, analyse, design, code, test and deploy. In this process, testing happens towards the end. Problems uncovered by testing at such a late stage can cause costly redesign and delays. The idea of Shift Left is to involve testing teams earlier in the process and to think about testing at all stages of the process.
When the software development process is viewed as a left-to-right sequential process, doing testing earlier may be seen as “shifting it to the left”. The term itself can be seen as a misnomer since we are not simply “shifting” but doing tests at all stages of the process.
Shift Left as a principle started with testing but it’s beginning to be employed in other disciplines such as security and deployment.
