Formal specification of extended refactoring guidelines

Refactoring is considered a disciplined and strict process of code restructuring. It requires evaluation of a complex set of pre and post conditions that ensure preservation of externally observable behavior and also improvement in the internal attributes of the software system. On the contrary refactoring process is rarely documented using formal methods of specification. We have found the existing formal/informal specifications of refactorings incomplete from the perspective of client and unit test adaptation. Also, these specifications do not take into account many semantic issues introduced by refactorings that are not flagged by the compiler. In this paper we have provided extended guidelines for key primitive refactorings. We have used these guidelines to develop a model for addressing adaptations in the clients and test code as well. We also provide formal specifications for: the functions in our model, a primitive refactoring and a composite refactoring.