Google today announced a new emulator tool for developers who are getting into Android Auto. The Desktop Head Unit will allow devs to properly work on Android Auto-compatible apps entirely in the virtual sense, all on your computer. You'll still need to connect your phone, but this will give a much better sense of what drivers will get from the app — all without having to actually get behind the wheel for testing.

Says Google:

The Desktop Head Unit (DHU) enables your development machine to emulate an Android Auto head unit, so you can easily run and test Android Auto apps. The DHU runs on Windows, Mac, and Linux hosts and replaces previous Android Auto simulators, such as the Android Media Browser and Messaging simulators.

The Desktop Head Unit also supports day and night modes, and you can test with voice input as well.

More: Google Developer Blog
Also: Desktop Head Unit help