prop_shrinkDF :: Instance.Instance -> Property
prop_shrinkDF inst =
  forAll (choose (0, 2 * Types.unitDsk - 1)) $ \dsk ->
    let inst' = inst { Instance.dsk = dsk, Instance.disks = [dsk] }
    in isBad $ Instance.shrinkByType inst' Types.FailDisk
prop_shrinkDF :: Instance.Instance -> Property
prop_shrinkDF inst =
  forAll (choose (0, 2 * Types.unitDsk - 1)) $ \dsk ->
    let inst' = inst { Instance.dsk = dsk, Instance.disks = [dsk] }
    in isBad $ Instance.shrinkByType inst' Types.FailDisk
prop_shrinkDF inst =
  forAll (choose (0, 2 * Types.unitDsk - 1)) $ \dsk ->
    let inst' = inst { Instance.dsk = dsk, Instance.disks = [dsk] }
    in isBad $ Instance.shrinkByType inst' Types.FailDisk