testBit' u (b:bs) n | n > 7 = testBit' u bs (n - 8)
                    | otherwise = B.testBit b (fromIntegral $ 7 - n)
testBit' u (b:bs) n | n > 7 = testBit' u bs (n - 8)
                    | otherwise = B.testBit b (fromIntegral $ 7 - n)
testBit' u (b:bs) n | n > 7 = testBit' u bs (n - 8)
                    | otherwise = B.testBit b (fromIntegral $ 7 - n)