Simply Business, a UK-based business insurance broker, has revamped their call center using Twilio's TaskRouter and Voice APIs. The company aimed to improve customer experience by reducing long hold times and repetitive information. They built an automated task router powered call center, which integrates with their existing application. To test the integration, they developed a set of end-to-end tests using RSpec, Capybara, and Turnip. These tests simulate real user interactions, allowing them to ensure the system works as expected. The tests cover various scenarios, such as receiving calls, hanging up, and handling call failures. To make the tests more efficient, they used Twilio's TwiML for automated phone responses and dynamically injected ngrok callback URLs. The tests are now run on Semaphore CI, a third-party continuous integration environment, where they save time and allow for internal code refactoring with confidence.