disk, err := findDeviceForPath("/dev/sde", io)
	if err != nil {
		t.Fatalf("error finding device for path /dev/sde:%v", err)
	}
	if disk != "sde" {
		t.Fatalf("disk [%s] didn't match expected sde", disk)
	}
	disk, err = findDeviceForPath("/returns/a/dev", io)
	if err != nil {
		t.Fatalf("error finding device for path /returns/a/dev:%v", err)
	}
	if disk != "sde" {

					return nil, err
				}

				mounts := []mount.MountPoint{
					{Device: "/dev/sdb", Path: file0},
					{Device: "/dev/sdc", Path: dir1},
					{Device: "/dev/sdd", Path: dir2},
					{Device: "/dev/sde", Path: file3},
				}
				return mounts, nil
			},
			unmount: func(mountpath string) error {
				err := filepath.Walk(mountpath, func(path string, info os.FileInfo, _ error) error {
					if path == mountpath {