A test plan is a precious written document that describes the testing strategy for a software or hardware project. It is a document that outlines the scope of testing, the resources needed, the test environment, and the test cases that will be executed. Its purpose is to ensure that the testing process is thorough and complete and that all necessary tests are conducted systematically and coordinated.
It acts as a detailed document to ensure the proper working of the software. The output from the testing phase is directly related to the quality of planning that went into it. These testing plans are usually developed during the development phase to save time for executing tests and reaching a mutual agreement with all the parties involved.