I recently learned how to use SOAP UI to test REST and SOAP Webservices. But now, I am looking for a similar open-source software to test Publish-Subscribe connections for performing automated testing. I want to use several test cases. Please suggest me tools that can do this.
In our team, we used SpecFlow to test the service based test cases.
If you need a tool to post HTTP messages for a functional tests, have a look at RestAssured, Karate, Postman.