WSO2 ESB Unit Testing

We've developed a Proxy Service into WSO2 ESB which is an orchestrator, and calls multiple services aggregating the response.

How can I test each single step (or mediator) of the proxy flow, and how the system reacts to each possible situation (e.g. Success, Failure, Slow response time...)?

We are trying to mock the behaviour of each service called by the proxy (with Wiremock), for each step, but we are not able to dynamically change the endpoints (or the ports) pointed by each call.

Example:

• Real service is listening on port 8280
• Wiremock is listening on port 8281
• We need to dynamically change the endpoint within the Proxy, to let it call the Wiremock service (8281) instead of the real one (8280)