Once the system requirements are understood and the scope of testing is defined the next stage is to produce a plan of how testing will be carried out.
A test (management) plan or test strategy should be produced. It defines the scope, approach, resources and schedule of intended test activities. It identifies amongst others test items, the features to be tested, the testing tasks, who will do each task, the test environment, the test design techniques and entry and exit criteria to be used, and the rationale for their choice, and any risks requiring contingency planning. It is a record of the test planning process.
Once the test plan is agreed by the stakeholders involved with the software delivery project it will become a basis for the acceptance of the final system.
by Herb Williams