Add a simple test to validate behavior with vDPA devices. Most of this
is simply fleshing out the fixtures we use to fake out vDPA devices and
generally tweaking things to make them better.
Change-Id: I1423d8a9652751b667463f90c69eae1a054dd776
Signed-off-by: Stephen Finucane <stephenfin@redhat.com>
Co-authored-by: Sean Mooney <work@seanmooney.info>