+import Test.HUnit (assertEqual)
+import Test.Framework (Test, testGroup)
+import Test.Framework.Providers.HUnit (testCase)
+import Test.Framework.Providers.QuickCheck2 (testProperty)
+import Test.QuickCheck (Arbitrary(..), Gen, Property, (==>))
+import Text.Read (readMaybe)
+
+import qualified Bit as B (Bit(..))
+import IPv4Address (IPv4Address(..), most_sig_bit_different)
+import Maskable (Maskable(..))
+import Maskbits (Maskbits(..))
+import Octet (Octet(..))