That is a great question, I am wondering the same thing and if it is not possible if an emulator can connect to a real usb controller. I tried looking online but havent found much so far.
Android Emulator doesn't support USB emulation yet (http://developer.android.com/tools/devices/emulator.html#limitations), so you cannot forward controller to it. You can anyhow use an Android x86 Image running inside VirtualBox, that does support USB forwarding and should be able to test it like that (haven't had the time yet to test it, but for other USB devices it works).
Comments
For the mapping of keys, doesn't seem to work (yet). But since the launcher and framework aren't open source (yet, http://forums.ouya.tv/discussion/61/open-source-the-launcher-and-framework) could not look into the sources (okay I could, but I am not in the mood to view the decompiled sources).