A Model-Based Test Case Prioritization Approach Based on Fault Urgency and Severity

Abstract

With the aggrandizement scale of software system, the number of test cases has grown explosively. Test case prioritization (TCP) has been widely used in software testing to effectively improve testing efficiency. However, traditional TCP methods are mostly based on software code and they are difficult to apply to model-based testing. Moreover, existing model-based TCP techniques often do not take the likely distribution of faults into consideration, yet software faults are not often equally distributed in the system, and test cases that cover more fault prone modules are more likely to reveal faults so that they should be run with a higher priority. Therefore, in this paper, we provide a TCP approach based on Hidden Markov Model (HMM), to detect faults as earlier as possible and reduce the cost of modification. This approach consists of the following main parts: (1) transforming the Unified Modeling Language (UML) sequence diagram to HMM; (2) estimating the fault urgency according to fault priority and probability; (3) estimating the fault severity by analyzing the weight of the state in the HMM; (4) generating test case priority from fault urgency and fault severity, then prioritizing test case. The proposed approach is implemented on unmanned aerial vehicles (UAV) flight control system to perform TCP. The experimental results show that our proposed TCP approach can effectively enhance the probability of earlier fault detection and improve the efficiency and stability as compared to other prioritization techniques, such as original prioritization, random prioritization, additional prioritization and EPS-UML.