Software testing practices in critical financial systems transformation

Critical financial transformation projects with large budgets have many different challenges. For companies that want to survive in conditions of tough competition, legacy (old) systems must continue to provide the required service throughout the project life cycle and in some circumstances even after project completion partly. In this case, the term coexistence comes into prominence. During this period, testing phase takes more critical role while integration systems´ complexity and risk amount increase. Determining testing approach to use is essential to make sure both transformed and legacy systems provide service synchronously. In this paper, testing practices applied in the long conversion processes are discussed. Primarily, the basic features of the critical financial systems are addressed and then the main adoption methods in the literature are summarized. Then a variety of testing methodologies are presented depending on those adoption methods. These samples based on real-life experiences of transformation project. The most extensive example of real-time online financial systems is core banking systems. This paper covers the testing life cycle process of the large scale project of core banking system transformation project of a bank in Turkey.