When doing BDD you should always mock the collaborators. The tests should run quickly and not depend on any external resources such as servers, APIs, databases etc.
The way you would want to make in f.e. Jasmine is to declare a spy that pretends to be the server. You then move on to defining what would be the response of the spy in a particular scenario or example.
This is the best aproach if you want your application to be environment undependent. Which is very needed when running Jenkins jobs - building a whole infrastructure around the job would be hard to reproduce.
Make spy/mock objects that represent the server and in your specs define how the external sources behave - this way you can focus on what behavior your application delivers under specified circumstances.