Abstract: An apparatus and method for generating and maintaining a regression test case set directly and automatically from requirements models. A user operating the invention generates a representation of a system which captures temporal, functional, life cycle or other relationships between requirements. These relationships specify the circumstances under which a requirement applies and places the requirement in the context of other requirements. Selection techniques applied to the representation generates test cases. A regression test case set is a set of test cases that are used by the user to verify functionality in view of modifications or additions to the system. As the features of the system are adjusted over the life cycle of the system, the method of the invention automatically provides a regression test case set that affords optical coverage with respect to all features of the system. Any regression test cases that fail are automatically detected and graphically displayed.