In this chapter, you understood various testing methodologies, different approaches to system migration and cutover techniques, and the objectives of post-implementation reviews. You also learned how to conduct post-implementation reviews of systems to determine whether project deliverables, controls, and requirements have been met. The following are some important topics covered in this chapter: • Unit tests include tests of each separate program or module. Testing is generally conducted by the developers themselves. They are conducted as and when a program or module is ready, and it is not necessary to wait until the entire system is completed. Unit testing is done through a white box approach wherein the internal program logic is tested. • System migration is the process of transferring IT resources (mostly data) to a new hardware or software platform with the objective of gaining better business value. • Changeover is the process of shifting to a new system and stopping the use of old systems. It is also known as the go-live technique or the cutover technique. Parallel changeover, phased changeover, and abrupt changeover are some ways to change to a new system. • In white box testing, the program logic is verified. To conduct white box testing, appropriate knowledge of a relevant programming language is a must. White box testing is generally conducted during unit testing. • Integration testing is performed to ensure the correct and accurate data flow between two or more systems. Integration testing aims to ensure the accuracy of the device interface's most critical components. • Regression testing is performed to ensure no errors have been introduced in improvements or corrections. Sociability testing is performed to ensure the new or changed system will operate without affecting the existing system. • Sociability is the quality of being able to merge with others. The objective of sociability testing is to ensure that the new system works as expected in the existing infrastructure without having any adverse impact on other existing systems. • A post-implementation review is conducted to determine the extent to which the project met its objectives and addressed the originally defined requirements, perform a cost-benefit analysis, determine the return on investment, and determine lessons learned from the project for the improvement of future projects. In the next chapter, we will discuss various aspects of information systems operations, such as technology components, asset management, incident management, and database management.