title: Integration testing with event sourcing systems
body: <p>I'm working on a PoC where we use CQRS in combination with Event Sourcing. We use the Axon framework and Axon server as toolset.</p>
  
  <p>We have some microservices (Maven packages) with some business logic.</p>
  
  <p>A simple overview of the application flow:</p>
  
  <p>We post a xml message (with REST) to service 1 that will result in an event (with Aggregate). 
  Service 2 handles the event "fired" by service 1 and starts a saga flow. Part of the sage flow is for example to send a mail message.</p>
  
  <p>I can do some tests with Axon Test to test the aggregate from service 1 or the saga from service 2. But is there a good option to do a real integration test where we start with posting a message to the REST interface and check all the operations in the aggregate and saga (inclusive sending mail and so on)</p>
  
  <p>Maybe this kind of integration test is overdone and it's better to test each component on it's own. I doubt what's needed / the best solution to test this type of system.</p>