Verification and validation are processes to ensure a software system meets user needs. Verification checks that the product is being built correctly, while validation checks it is the right product. Both are life-cycle processes applying at each development stage. The goal is to discover defects and assess usability. Testing can be static like code analysis or dynamic by executing the product. Different testing types include unit, integration, system, and acceptance testing. An effective testing process involves planning test cases, executing them, and evaluating results.