How to change Jetty port number for SwitchYardRunner based unit test

Issue

• We have a SwitchYard 2.x SOAP web-service and have created an initial JUnit 4/SwitchYardRunner based unit test to exercise this service.
  When the unit tests run, the SwitchYardRunner attempts to spawn a Jetty instance on port 8080 to allow the tests to proceed. On a local developer machine this is not ideal, but on the CI server this is not suitable because our Jenkins instance is running on port 8080.

• We would like to know how, assuming it is possible, to configure the unit test to run the Jetty instance on a different port to avoid the clash with port 8080.