The qualitative factor in software testing: A systematic mapping study of qualitative methods

Software testing research has provided metrics on efficiency, error rates, and insights into the effectiveness of testing methodologies and tools. However, these tell only a part of the story. The qualitative dimension, which studies experiences, perceptions, and decision-making processes is crucial, but less prevalent in literature. This study aims to systematically map qualitative research in software testing to consolidate and categorize the methodologies used in qualitative testing research, highlight their importance, and identify patterns, gaps, and future directions. We conducted a systematic mapping study, identifying and analyzing 102 primary studies from 2003 to 2023. We categorized the studies according to research strategies, data collection, and data analysis methods. We identified case studies and grounded theory as the most prevalent research strategies. Researchers primarily used semi-structured interviews and thematic analysis to understand how practitioners work and gather stakeholder perspectives. The subject areas most covered by qualitative studies included software testing processes and risks, and test automation. Areas such as test oracles, and machine learning were underrepresented. We also assessed the quality of reporting and the methodological rigor, emphasizing the challenges and limitations identified during the process. Through this study, we provide a comprehensive overview of qualitative research practices in software testing, revealing trends, gaps, and methodological insights.