Testing of any storage-related software will generally require access to some writeable/non-OS block devices. This will be true for everything from lvm to xfsprogs to libblockdev, blivet, etc.

If this is to be useful, it should be possible to specify the number of disks and their sizes. Optionally, it would also allow specifying other properties as supported by qemu (bus, serial number, maybe sector size, etc.).

I have some existing integration tests in blivet[1] that could be converted to use this framework, and am currently developing an ansible role[2] for managing storage that would use this functionality as well.

[1] https://github.com/storaged-project/blivet/blob/3.1-devel/tests/vmtests/runvmtests.py
[2] https://github.com/dwlehman/linux-storage-role