Desktop Head Unit - Android Auto
Unless you want to build yourself a DIY Android Auto unit for your desk, developing for Android Auto can be a bit of a hassle. But it seems Google is aware of that and has this morning announced the Android Auto Desktop Head Unit (DHU), an official tool for developers to use to work on the platform from their PC.

Google describes the setup:

The DHU enables your workstation to act as an Android Auto head unit that emulates the in-car experience for testing purposes. Once you’ve installed the DHU, you can test your Android Auto apps by connecting your phone and workstation via USB. Your phone will behave as if it’s connected to a car. Your app is displayed on the workstation, the same as it’s displayed on a car.

Google has provided further documentation on installing and setting up the Desktop Head Unit for anyone interested in trying it out.

Source: Android Developers.