Shift-left testing is an approach that involves moving testing activities to earlier stages of the software development lifecycle (SDLC) to catch defects early, improve software quality, and reduce costs. There are four basic ways to shift testing earlier in the life-cycle, leftward on the classic V-model, which include traditional shift-left testing, incremental shift-left testing, Agile/DevOps shift-left testing, and model-based shift-left testing[8]. Traditional shift-left testing involves integrating testing activities into every phase of the process, while incremental shift-left testing gradually moves testing activities to earlier stages of the SDLC. Agile/DevOps shift-left testing involves continuous testing throughout the development process, using automated testing tools and practices like continuous integration and continuous testing (CI/CT). Model-based shift-left testing uses models to simulate software behavior and identify defects early in the development process.
