Final answer:
Software testing should start as early as possible in the development life cycle, preferably during the design stage. Early testing allows for problems to be identified and resolved quickly, and aligns with the shift-left testing approach.
Step-by-step explanation:
Software testing activities should ideally begin as early as possible in the development life cycle. This aligns with a proactive approach known as shift-left testing, which emphasizes testing early in the software development process. By initiating testing during the design stage, potential issues can be identified and resolved before the development progresses too far, saving time and resources. Additionally, testing at this stage allows for the evaluation of requirements and constraints and ensures that the design adheres to these guidelines. Continuous testing throughout the development process, including during detailed design, can lead to a more refined product and often results in a more reliable and effective software solution. Upon completion of testing and evaluation, it may be necessary to refine the design based on feedback and test results to better meet the project's goals.