Correcting for unreliable regression integration testing

H. Leung and L. White (1990) introduced the firewall concept for control flow in regression testing. In order to define this firewall, they assumed that unit testing and integration testing are both reliable. The paper continues to assume that unit testing can be carried out in an entirely reliable fashion, while integration testing may not be reliable. The paper is designed to fulfill the following objectives: identify the error cases that the testing process may have missed, making integration testing unreliable; attempt to solve the problems that make integration testing unreliable, designing procedures to improve reliability; and determine the effects of unreliable integration testing on the firewall, indicating how the firewall construction should subsequently change.