3 files changed, 39 insertions, 8 deletions

diff --git a/src/Data/Bitfield.hs b/src/Data/Bitfield.hs
index 3424a0c6..a1033ff2 100644
--- a/src/Data/Bitfield.hs
+++ b/src/Data/Bitfield.hs
@@ -19,6 +19,7 @@ module Data.Bitfield
        , haveAll, haveNone, have
 
          -- * Query
+       , Data.Bitfield.null
        , haveCount, totalCount, completeness
        , findMin, findMax
 
@@ -100,6 +101,10 @@ have ix Bitfield {..}
     Query
 -----------------------------------------------------------------------}
 
+-- | Test if bitifield have no one index: peer do not have anything.
+null :: Bitfield -> Bool
+null Bitfield {..} = S.null bfSet
+
 -- | Count of peer have pieces.
 haveCount :: Bitfield -> PieceCount
 haveCount = S.size . bfSet
diff --git a/tests/Encoding.hs b/tests/Encoding.hs
index 8afd3625..a599cd39 100644
--- a/tests/Encoding.hs
+++ b/tests/Encoding.hs
@@ -35,7 +35,8 @@ instance Arbitrary Block where
   arbitrary = Block <$> positive <*> positive <*> arbitrary
 
 instance Arbitrary Bitfield where
-  arbitrary = mkBitfield <$> (succ <$> positive) <*> arbitrary
+  arbitrary = mkBitfield <$> (succ . min 1000 <$> positive)
+                         <*> arbitrary
 
 instance Arbitrary PortNumber where
   arbitrary = fromIntegral <$> (arbitrary :: Gen Word16)
diff --git a/tests/Main.hs b/tests/Main.hs
index ef4ab8a7..0aa6423f 100644
--- a/tests/Main.hs
+++ b/tests/Main.hs
@@ -16,23 +16,48 @@ import Network.BitTorrent as BT
 
 import Encoding
 
-
-
-instance Arbitrary IntSet where
-  arbitrary = fromList <$> arbitrary
+{-----------------------------------------------------------------------
+    Bitfield
+-----------------------------------------------------------------------}
+-- other properties are tested in IntervalSet
 
 prop_completenessRange :: Bitfield -> Bool
 prop_completenessRange bf = 0 <= c && c <= 1
   where
     c = completeness bf
 
+prop_minMax :: Bitfield -> Bool
+prop_minMax bf
+  | BF.null bf = True
+  | otherwise  = BF.findMin bf <= BF.findMax bf
+
 prop_rarestInRange :: [Bitfield] -> Bool
 prop_rarestInRange xs = case rarest xs of
-  Just r  -> 0 <= r && r < totalCount (maximumBy (comparing totalCount) xs)
+  Just r  -> 0 <= r
+          && r < totalCount (maximumBy (comparing totalCount) xs)
   Nothing -> True
 
+{- this one should give pretty good coverage -}
+prop_differenceDeMorgan :: Bitfield -> Bitfield -> Bitfield -> Bool
+prop_differenceDeMorgan a b c =
+  (a `BF.difference` (b `BF.intersection` c))
+     == ((a `BF.difference` b) `BF.union` (a `BF.difference` c))
+  &&
+  (a `BF.difference` (b `BF.union` c))
+     == ((a `BF.difference` b) `BF.intersection` (a `BF.difference` c))
+
+
+{-----------------------------------------------------------------------
+    Torrent
+-----------------------------------------------------------------------}
+
+-- TODO tests for torrent: encoding <-> decoding
+
+
 main :: IO ()
 main = defaultMain
-  [ testProperty "completeness range" prop_completenessRange
-  , testProperty "rarest in range"    prop_rarestInRange
+  [ testProperty "completeness range"      prop_completenessRange
+  , testProperty "rarest in range"         prop_rarestInRange
+  , testProperty "min less that max"       prop_minMax
+  , testProperty "difference de morgan"    prop_differenceDeMorgan
   ]