The unit tests mock QMP and the guest agent, so they cannot catch a wrong
argument name, a QEMU option that stopped parsing, or a reply shape that
differs from the fake. This suite drives the real thing: the qemu-img
toolchain, lifecycle and see-and-drive on a diskless BIOS VM, adopting a
forgotten VM through attach_vm, the refusal to reuse a live socket, and the
full sandbox journey (guest exec, file round trip, live snapshot create /
restore / delete verified by guest state, screenshot) with a check that the
base image is never modified.
It immediately earned its keep: pid_matches_vm was rejecting attached VMs,
because an externally launched QEMU carries whatever -name its launcher
chose, so adopting one under a different name made it read as stopped. The
identity check now applies only to VMs we spawned.
