Object-oriented technology impact on overall area of software engineering. O-O paradigm for software development introduces a number of new concepts, such as class, inheritance, encapsulation, dynamic binding, and polymorphism. They not only introduce new testing problems but they raise a new challenging question of how to conduct regression testing for O-O programs. The first problem of regression testing is how to identify the affected components due to changes of some components.
We propose a method firewall to enclose all the classes and methods affected by changes to one or more methods in method level. We divide the class relations into three categories, inheritance, aggregation and association, and provide algorithms for identify the affected part according to relation type in method level.
