How can I simulate an outside system that uses MQ?

"In a real test scenario I have one test system which connects to outside system using MQ in production. How can I simulate that outside system in my test environment? Let me give example: XYZ Bank sends a message to processing system with XML fields of ACCNO, NAME, AMT, DATE etc. I am a tester of XYZ Bank Application. I want to verify the request and response. How can I do that? I am a sender and receiver but other system is outside my test environment. How to simulate it?" (source)

The simulator you are referring to is typically called a mock, stub or virtual service. If you would like to simulate the outside system to enable testing of your application you should use a mocking tool (also called service virtualization). Just make sure you use a tool that supports IBM MQ. An example of a tool that can simulate and mock IBM MQ for the purpose of testing is Traffic Parrot.