# Ontology-Based Regression Testing: A Systematic Literature Review
## 4 Results and Discussion
### RQ3: What Are the Challenges and Limitations of Current Approaches? To answer RQ3, the authors presented the challenges and limitations identified in the ontology-based regression testing approaches. These limitations and challenges are given as follows:  
* Validation of approaches. Although test case grouping presented in [39] helps remove the failed services, it still shows limitations in prioritizing test cases as low prioritized test cases might be grouped with the high prioritized test case [43]. Grouping high and low priority test cases is justified and plausible only if it is supported by previously evaluated criteria [22; 42]. * Cost. To separate the failed test cases, all test cases of an application are rerun, which is expensive regarding the testing cost [45; 46]. Adaptive testing is a steady job that requires sources for testing web services. The cost issue is widely identified in ontology-based studies [41; 42; 47]. * Scalability. The scalability and applicability of the proposed TCP approaches on real-world web applications are other limitations of the existing research studies [22; 39; 40] regarding ontology-based TCP in regression testing. * Risk assessment. Application output behavior and risky scenarios are also not addressed in these research studies [22; 39]. Study [39] presented a model based on the semantics from the workflow of web services, ontology usage, and ontology dependency to identify the contributing risks during the execution of web services. At the same time, the risk of errors was not taken into account while web systems were updated during the execution of tasks. To prevent or reduce such errors is an open question for researchers [22]. * Reliability. Web systems' reliability in terms of regression testing is missed in the existing studies. A study [40] proposed a risk assessment approach for the ranking of test cases. Researchers in this study considered risk assessment in the context of users' input/output and pre/post conditions, processes, and ontology constraints. The risk assessment covers the dissatisfaction of regulatory/legal requirements and relates mainly to a process, work, or project that does not achieve the expected functional behavior. The proposed TCP approach does not involve the reliability of web services. A product risk carefully refers to \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Authors** & **Problem** & **Proposed Technique** & **Advantage** & **Limitation** \\ \hline [PERSON] et al. [37] & High cost on web & An automated testing & Effective prioritization & No cost resources were used in the proposed \\  & services testing & framework & of web services & \\ \hline [PERSON] et al. [38] & An increase in cost due & Semantic-based & Faults detection is & \\  & to source code & prote\(\breve{\text{g}}\)e tool & better than the & Coverage criteria is not \\  & unavailability & & traditional approaches & clearly mentioned \\ \hline [PERSON] et al. [40] & Web services testing in & A risk-based approach & Faults detection with a & The reliability of web \\  & an open platform & using semantics & high impact & services is not \\  & & & & mentioned \\ \hline [PERSON] et al. [41] & Handling changes in & Regression test & Reduces the overall & This approach might \\  & the evolving system is a & & selection & time to rerun test cases & have missed some \\  & difficult task & & & necessary test cases \\ \hline [PERSON] et al. [43] & Validation of tests in an & Domain-specific & Systematic generation & The cost to ensure the \\  & ad hoc fashion & ontology-based & of TCG from safety & safety of a web system \\  & & approach & analysis report & is not mentioned \\ \hline [PERSON] et al. [44] & Uncertain test coverage & Domain-specific & Ensures users’ safety, & Validation of web \\  & from random testing & ontology using & more effective than & systems at large-scale \\  & requirements & random testing & systems is not done \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Summary of ontology-based approaches.