What isi the proper way to make test code for an application getting message from MQ server?

I made an application that connect to MQ server and getting message then do something with the message.

But I don't get how to make a test code for this kind of application.

Is there a way to make a fake message to send to the function subscribe?

the below code is I wrote for the application

def subscribe(mq_server):
       // connecting to the server and return message
       return messages


def get_message():
    while True:
        //getting message from MQ server
        messages = subscribe(mq_server)
        // do something with the messages


if __name__ == '__main__':
    get_message()