prop_group xs n = n > 0 ==>
                  runner2 (enumPure1Chunk xs $ Iter.group n stream2list)
                  == runner1 (enumPure1Chunk groups stream2list)
  where types = xs :: [Int]
        groups :: [[Int]]
        groups = List.unfoldr groupOne xs
          where groupOne [] = Nothing
                groupOne elts@(_:_) = Just . splitAt n $ elts
prop_group xs n = n > 0 ==>
                  runner2 (enumPure1Chunk xs $ Iter.group n stream2list)
                  == runner1 (enumPure1Chunk groups stream2list)
  where types = xs :: [Int]
        groups :: [[Int]]
        groups = List.unfoldr groupOne xs
          where groupOne [] = Nothing
                groupOne elts@(_:_) = Just . splitAt n $ elts
prop_group xs n = n > 0 ==>
                  runner2 (enumPure1Chunk xs $ Iter.group n stream2list)
                  == runner1 (enumPure1Chunk groups stream2list)
  where types = xs :: [Int]
        groups :: [[Int]]
        groups = List.unfoldr groupOne xs
          where groupOne [] = Nothing
                groupOne elts@(_:_) = Just . splitAt n $ elts