When software is developed, a set of actions are planned. It has development, testing, and operations. I have shared a short and crisp video for the same. Watch it now. The development has 3- components. Designing and architecture helps to give an outline to the project. Unit testing and coding help to execute the plan.
The QA has a testing strategy. Testing strategy is very important to check the code quality. It also checks the expertise of the programmer. Nowadays, testing is automated. Then comes the operations. Deploying the output outside the box to check its performance. Infrastructure is really important for deployment. Meanwhile, monitoring must be done to check if any error or exception has come.