Build Android Studio project to Android version 15 with UiAutomator in project

My problem is that I want to build my application for older android devices, but I use UiAutomator for my tests which requires at least api level 18. Of course I run my tests on a device that has newer android version, but my application supports android version 15 except the tests. What can I do besides changing the minSdkVersion every time I run a test or upload my app on an older device?

Thank you for your assistance!