Testing is difficult and expensive, and testing distributed system even more difficult due to issues such as interoperability, collaboration, synchronization, Timing, and concurrency. A Tester often needs to spend significant time in developing lengthy testing code to ensure that the System Under Test (SUT) is reasonably well tested. This paper proposes an Object-Oriented (OO) framework to test distributed system rapidly and adaptively by using scenario modeling, state modeling, verification patterns, design patterns, regression testing, ripple effect analysis, simulation, automated test execution, and remote testing using TCP/IP or SOAP. Finally, this paper uses a supply-chain example to illustrate the key concepts.