Generating Test Cases for Overloaded Object-Oriented Programs using EGS (Extended General State-charts)

Overloading and polymorphism are two important aspects in object-oriented programming languages. When an class has either of these two specialities and is depicted with a state-chart which characterizes the behaviour of the class, problems arise. Such as different transition arcs are labelled with the same name but may represent similar duties on that state-chart. General state-charts (GS) can be used as patterns to model the overloading and polymorphism aspects of C++ programs. Furthermore, method functions can be mapped to a general state-chart to form an extended general state-chart (EGS). From these, state-transition trees can be generated. Errors, which occurs when overloaded/polymorphism functions are invoked against the wrong object, are hard to detect by state-based testing. This is because the resultant states after executing the messages could be the same as the expected states. In this class (unit) testing paper, we try to use EGS to produce legal and illegal test cases in order to test a class which has overloaded functions. The illegal test cases show all possible misusages of the overloaded functions.