Huan Pang; Noman Latif MSE-2011:57, pp. 152. COM/School of Computing, 2011.
Context: Exploratory Testing (ET) and Scripted Testing (ST) are two of the more commonly practiced manual testing approaches in industry. ST is a traditional testing approach in which testing is carried out by executing pre-designed test cases. While in ET, learning, test designing and test execution are carried out simultaneously. In many instances, ET and ST complement each other very well in projects; however, proponents of ET claim that ET is more cost-beneficial in comparison to ST. Moreover, a few studies have indicated that ET is more effective in defect detection. Nevertheless, to the best of our knowledge, no study has been conducted to compare the costs and benefits of these two approaches.
Objectives: The aim of this study was to conduct a qualitative Cost-Benefit Analysis (CBA) of ET in comparison with ST. By comparing and analyzing these two testing approaches, this study attempts to aid in decision-making with respect to how resources should be allocated for ET and ST for certain projects.
Methods: The factors of costs and benefits of ET and ST were identified by conducting six semi-structured interviews in industry. Based on the analysis of these factors, a CBA model is proposed. The academic and industrial evaluation of the proposed CBA model was performed by conducting five interviews with researchers and practitioners. In addition, a qualitative CBA of a process of ET, Session-Based Testing Management (SBTM), and a process of ST, Test-Case Based Testing (TCBT) is conducted by collecting data through questionnaires and interviews with industry practitioners. A total of 22 questionnaire responses and seven interviews were analyzed.
Results: By analyzing the identified cost and benefit factors, a CBA model was developed based on the testing phases stated in the ISO/IEC 29119 standard. A qualitative CBA of the SBTM process in comparison with the TCBT process was conducted by applying the CBA model in a questionnaire. The following findings were gathered from the CBA:
• The differences of the SBTM and TCBT processes are identified by an analysis of the activities performed in various organizations, which the respondents belonged to.
• The results of the analysis and comparison, of the costs (in terms of effort) and benefits (quality of the testing activities) of these two testing processes, are presented with respect to each testing phase.
• The factors that impact the costs and benefits of using SBTM and TCBT, are summarized and discussed in this report.
• The scenarios, in which SBTM and TCBT can be more cost-beneficial, are identified based on practitioners’ opinions.
Conclusions: According to the survey results, industry practitioners consider SBTM as more cost-beneficial in comparison with TCBT, particularly in the test design, implementation and test execution phases. However, industry practitioners also stressed that ET should not be considered as a replacement for ST. In some contexts, testing objectives are better achieved through a more scripted approach, while, in other contexts, testing objectives will benefit more from the ability to create and improve tests as they are being executed. Whether a testing approach is valuable or cost-beneficial also depends on the context of project and the required benefits.