In general, a document that describes test requirements. In the testplan editor, a test plan is displayed in an easy-to-read outline format, which lists the test requirements in high-level prose descriptions. The structure can be flat or many levels deep. Indentation indicates the level of detail. A test plan also contains statements, which are keywords and values that implement the test descriptions by linking them to 4Test test cases. Large test plans can be divided into a master plan and one or more sub plans. A test plan file has a .pln extension, such as find.pln.