I am required to build automated functional tests for an older web application which does not have much in the way of services or API. Normally that would mean using something like Selenium and interacting through a browser, but the automation has to go through our continuous integration, so it can't run through the browser UI.
We are using Jules for CI and build, and the automation has to succeed for the build to pass. Our team is trained in Selenium automation.
I don't know where to start. What tools are there to perform functional testing against an application that doesn't have an API when there is no way to open a browser and test with it?