On the economics of requirements-based test case prioritization

Software testing is a strenuous and expensive process. At least 50% of the total software cost is spent on testing activities 12. Companies are often faced with time and resource constraints that limit their ability to effectively complete testing efforts. Companies generally save suites for reuse; test suite reuse accounts for almost half of the maintenance cost 9. As the product goes thru several versions, executing all the test cases in a test suite can be expensive 9. Prioritization of test cases can be cost effective when the time allocated to complete testing is limited 9. Test case prioritization (TCP) involves the explicit planning of the execution of test cases in a specific order and is shown to improve the rate of fault detection 3, 9. The current software TCP techniques are primarily coverage-based (statement, branch or other coverage) 3,9. Coverage-based white-box prioritization techniques are most applicable for regression testing at the unit level and are harder to apply on complex systems 2. These techniques require testers to read and understand the code, which can be time consuming 2, and may assume that all faults are equally severe.