Test driver for developing USB Devices?

I've recently finished up Linux Device Drivers and have had moderate success writing the device (as opposed to host) side code for a dev board. For most applications, indeed almost all applications in the embedded world, it is sufficient to pose as a serial device. The ACM driver gives me some idea of what to do in the event that it *isn't* sufficient. However, my impression is that USB drivers tend to be very buggy, especially from vendors trying to go "off the beaten path". (My heart goes out to all the digital artists whose drawing tablet drivers break every couple months) In an effort to not be that guy, I'm curious what kinds of verification options are available on Linux. I had the idea of a "dummy" USB kernel driver whose job is to bind to a specific device and check it for common issues; e.g. non-compliant timing, weird power state behavior, deadlocks, performance. Does such a thing exist out there? I'm aware of the company Totalphase, which makes tools that can verify the physical (cable) layer, but I haven't found anything for the software on either side of said cable.