The V-model is a development life cycle model that shows the relationship between each phase of development and its corresponding phase of testing. In this model, each level of testing (unit testing, integration testing, system testing, acceptance testing) has a corresponding level of development (component design, component integration, system design, requirements analysis). The model also shows that testing activities should start as early as possible in the development process and that each level of testing should be planned and designed in parallel with its corresponding level of development. Therefore, one of the roles of a tester in a software company that adopts the V-model is to coordinate the test strategy with the project managers who are responsible for planning and managing each phase of development. This role involves defining the scope, objectives, approach, resources, schedule, risks, and deliverables of each level of testing in alignment with the development plan and the project requirements. You can find more information about the V-model and test planning in Software Testing Foundations: A Study Guide for the Certified Tester Exam, Chapter 22.