UCov: a user‐defined coverage criterion for test case intent verification

Abstract

The goal of regression testing is to ensure that the behavior of existing code, believed correct by previous testing, is not altered by new program changes. We argue that the primary focus of regression testing should be on code associated with: a) earlier bug fixes; and b) particular application scenarios considered to be important by the tester. Existing coverage criteria do not enable such focus, e.g., 100% branch coverage does not guarantee that a given bug fix is exercised or a given application scenario is tested. Therefore, there is a need for a new and complementary coverage criterion in which the user can define a test requirement characterizing a given behavior to be covered as opposed to choosing from a pool of pre-defined and generic program elements. We propose this new methodology and call it UCov, a user-defined coverage criterion wherein a test requirement is an execution pattern of program elements and predicates. Our proposed criterion is not meant to replace existing criteria, but to complement them as it focuses the testing on important code patterns that could go untested otherwise. UCov supports test case intent verification. For example, following a bug fix, the testing team may augment the regression suite with the test case that revealed the bug. However, this test case might become obsolete due to code modifications not related to the bug. But if an execution pattern characterizing the bug was defined by the user, UCov would determine that test case intent verification failed. It is also worth mentioning that our methodology paves the way for test case intent preservation, e.g., a failed verification could be followed by automated test case generation, the subject of future work. We implemented our methodology for the Java platform and applied it onto two real life case studies. Our implementation comprises the following: 1) an Eclipse plugin allowing the user to easily specify non-trivial test requirements; 2) the ability of cross referencing test requirements across subsequent versions of a given program; and 3) the ability of checking whether userdefined test requirements were satisfied, i.e., test case intent verification.

A mapping study on testing non-testable systems

“…This means that test execution can be cheaper in N-version Testing in comparison to manual approaches; thus N-version Testing could be cheaper if a large number of test cases are required. It might be necessary to generate additional test cases because of software maintenance (Assi et al 2016). Thus, the requirement for a larger number of test cases might be correlated with update frequency.…”

Resolving the Equivalent Mutant Problem in the Presence of Non-determinism and Coincidental Correctness

“…UCov is a test case coverage adequacy assessment tool for regression testing [3]. Like IMT, UCov leverages execution trace behaviours to achieve its objective.…”

“…Given their similarities, some of UCov's findings are relevant for IMT. For example, the aforementioned knowledge has been found to be available in the SUT's documentation [3].…”