There are commercial test products that are "dumb" enumerators. I used to have some in the lab I worked at. You can script low level usb commands to them and s

There are commercial test products that are "dumb" enumerators. I used to have some in the lab I worked at. You can script low level usb commands to them and see how the device responds. Here is an example that is pretty simple. http://www.rpmsys.com/root_flyer.pdf http://www.rpmsys.com/root_flyer.pdf I can't remember what it costs, I think it was about $2k This is a more expensive elaborate one. http://ellisys.com/products/usbex260/index.php http://ellisys.com/products/usbex260/index.php Again I can't remember the cost, but I think it was about $30K or so. Anyway in theory with a device like this you could develop a test to check a device actually only performed the functions it was supposed to, like for instance it never changed its USB descriptors from the function it was supposed to have.