Insights into testing and regression testing global variables

Despite the existence of global variables in many software systems, testing global variables has traditionally been overlooked by the testing community. This state of the practice leads to the release of some software systems with untested properties. In this paper, we present some insights into the problem of testing and regression testing global variables. A basis set of testing problems for parameters will be identified and the testing problem of global variables will be mapped onto a combination of these basis cases. It will be shown that global variables can be treated as parameters and can be tested accordingly. Testing strategies and regression testing strategies for unit, integration, and system testing global variables are described.