prop_groupBy xs = forAll (choose (2,5)) $ \m ->
  let pred z1 z2 = (z1 `mod` m == z2 `mod` m)
  in runner2 (enumPure1Chunk xs $ Iter.groupBy pred stream2list)
       == runner1 (enumPure1Chunk (List.groupBy pred xs) stream2list)
  where types = xs :: [Int]
prop_groupBy xs = forAll (choose (2,5)) $ \m ->
  let pred z1 z2 = (z1 `mod` m == z2 `mod` m)
  in runner2 (enumPure1Chunk xs $ Iter.groupBy pred stream2list)
       == runner1 (enumPure1Chunk (List.groupBy pred xs) stream2list)
  where types = xs :: [Int]
prop_groupBy xs = forAll (choose (2,5)) $ \m ->
  let pred z1 z2 = (z1 `mod` m == z2 `mod` m)
  in runner2 (enumPure1Chunk xs $ Iter.groupBy pred stream2list)
       == runner1 (enumPure1Chunk (List.groupBy pred xs) stream2list)
  where types = xs :: [Int]