At Simply Business we insist that applications use TDD, CI and CD. To create our Twilio-based dialler, we needed to automatically test our live Twilio integration in order to enable deploys while our contact centre is on the phones. Here, we will show you what we did. You will learn how to take a simple Twilio app and test it on a CI platform (using Ruby). We will cover challenges such as Twilio callbacks with an unknown host IP and WebRTC calls using a headless browser.