Testing is a crucial activity to maintain high quality standards and achieve long-lasting economic success. However, integrating voice control into apps prevents the use of test automation tools. Testing speech-based interaction is still manual work: repetitive, time-consuming, and error-prone. Consequently, a need for specialized software engineering methods exists. We present an approach to test automation for speech-based applications by integrating an audio injection test interface into the Android operating system. Our approach enables developers to integrate voice control into automatically executed user acceptance tests using the Calabash test automation framework.