Cost Effectiveness of Unit Testing: A Case Study in a Financial Institution

This paper presents a case study on the cost effectiveness of unit testing in the context of a financial institution in Costa Rica. The study comprises four main steps: choosing a software application, implementing unit tests for this application, identifying prevented defects, and performing a cost and savings analysis. The impact of unit testing on the quality of software is assessed in terms of early defect detection, and the impact on the overall cost of software is evaluated based on the cost of developing the unit tests and the savings derived from the reduction of defects in later phases of the application development lifecycle. Our results indicate that while unit testing could help early defect detection, the monetary cost associated to unit testing would be higher than the monetary savings, in the particular context of the financial software studied, and under the limitations of our cost-savings model.