Exploratory testing: a multiple case study

Exploratory testing (ET) - simultaneous learning, test design, and test execution - is an applied practice in industry but lacks research. We present the current knowledge of ET based on existing literature and interviews with seven practitioners in three companies. Our interview data shows that the main reasons for using ET in the companies were the difficulties in designing test cases for complicated functionality and the need for testing from the end user´s viewpoint. The perceived benefits of ET include the versatility of testing and the ability to quickly form an overall picture of system quality. We found some support for the claimed high defect detection efficiency of ET. The biggest shortcoming of ET was managing test coverage. Further quantitative research on the efficiency and effectiveness of ET is needed. To help focus ET efforts and help control test coverage, we must study planning, controlling and tracking ET.