diff --git a/ChangeLog b/ChangeLog
new file mode 100644
--- /dev/null
+++ b/ChangeLog
@@ -0,0 +1,24 @@
+Changes in 0.1.1.1
+
+  * Type level addition is fixed for GHC 7.6
+
+  * Test suite added to cabal file
+
+	
+Changes in 0.1.1.0
+
+  * withNat, withInt, SomeNat and SomeInt added.
+
+
+Changes in 0.1.0.3
+
+  * Fix build for GHC 7.4
+
+
+Changes in 0.1.0.2:
+
+  * Fix URL in cabal file
+
+Changes in 0.1.0.1:
+
+  * Workaround for GHC bug #4364 (Build failure on GHC 7.0)
diff --git a/TypeLevel/Number/Int.hs b/TypeLevel/Number/Int.hs
--- a/TypeLevel/Number/Int.hs
+++ b/TypeLevel/Number/Int.hs
@@ -145,7 +145,10 @@
 
 type family   AddBit n :: *
 type instance AddBit    ZZ = ZZ
-type instance AddBit (a b) = D0 (a b)
+type instance AddBit (Dn a) = D0 (Dn a)
+type instance AddBit (D0 a) = D0 (D0 a)
+type instance AddBit (D1 a) = D0 (D1 a)
+
 
 type instance Normalized     ZZ = ZZ
 type instance Normalized (Dn n) = Dn     (Normalized n)
diff --git a/TypeLevel/Number/Nat.hs b/TypeLevel/Number/Nat.hs
--- a/TypeLevel/Number/Nat.hs
+++ b/TypeLevel/Number/Nat.hs
@@ -198,7 +198,8 @@
 -- equal to zero. Actual normalization is done here.
 type family   Add0Bit n :: *
 type instance Add0Bit    Z  = Z
-type instance Add0Bit (a b) = (O (a b))
+type instance Add0Bit (O n) = (O (O n))
+type instance Add0Bit (I n) = (O (I n))
 
 type instance Normalized    Z  = Z
 type instance Normalized (I n) = I (Normalized n)
diff --git a/test/TestNat.hs b/test/TestNat.hs
new file mode 100644
--- /dev/null
+++ b/test/TestNat.hs
@@ -0,0 +1,60 @@
+{-# LANGUAGE TemplateHaskell #-}
+module TestNat where
+       
+import Language.Haskell.TH
+import Text.Printf
+
+import TypeLevel.Number.Nat as N
+import TypeLevel.Number.Int as I
+
+
+----------------------------------------------------------------
+-- Natural numbers
+
+testAdd :: Integer -> Integer -> ExpQ
+testAdd n m = 
+  [| let flag = (n+m) == (N.toInt $ addN (undefined :: $(natT n)) (undefined :: $(natT m)) :: Integer)
+     in test "+" n m flag
+   |]
+
+testSub :: Integer -> Integer -> ExpQ
+testSub n m = 
+  [| let flag = (n-m) == (N.toInt $ subN (undefined :: $(natT n)) (undefined :: $(natT m)) :: Integer)
+     in test "-" n m flag
+   |]
+
+testMul :: Integer -> Integer -> ExpQ
+testMul n m = 
+  [| let flag = (n*m) == (N.toInt $ mulN (undefined :: $(natT n)) (undefined :: $(natT m)) :: Integer)
+     in test "*" n m flag
+   |]
+
+----------------------------------------------------------------
+-- Integer numbers
+
+testAddZ :: Integer -> Integer -> ExpQ
+testAddZ n m = 
+  [| let flag = (n+m) == (I.toInt $ addN (undefined :: $(intT n)) (undefined :: $(intT m)) :: Integer)
+     in test "+" n m flag
+   |]
+
+testSubZ :: Integer -> Integer -> ExpQ
+testSubZ n m = 
+  [| let flag = (n-m) == (I.toInt $ subN (undefined :: $(intT n)) (undefined :: $(intT m)) :: Integer)
+     in test "-" n m flag
+   |]
+
+testMulZ :: Integer -> Integer -> ExpQ
+testMulZ n m = 
+  [| let flag = (n*m) == (I.toInt $ mulN (undefined :: $(intT n)) (undefined :: $(intT m)) :: Integer)
+     in test "*" n m flag
+   |]
+
+test :: String -> Integer -> Integer -> Bool -> IO Bool
+test op n m flag = do
+  _ <- printf "%3i  %s %3i : %s\n" n op m (text flag)
+  return flag
+  where
+    text :: Bool -> String
+    text True  = "OK"
+    text False = "Failed"
diff --git a/test/int.hs b/test/int.hs
new file mode 100644
--- /dev/null
+++ b/test/int.hs
@@ -0,0 +1,16 @@
+{-# LANGUAGE TemplateHaskell #-}
+import Control.Applicative
+import Language.Haskell.TH
+import System.Exit
+
+import TestNat
+
+
+main :: IO ()
+main = do
+  plus  <- sequence $(listE (testAddZ <$> [-9..9] <*> [-9..9]))
+  minus <- sequence $(listE (testSubZ <$> [-9..9] <*> [-9..9]))
+  mult  <- sequence $(listE (testMulZ <$> [-9..9] <*> [-9..9]))
+  case and $ plus ++ minus ++ mult of
+    True  -> exitSuccess
+    False -> exitFailure
diff --git a/test/nat.hs b/test/nat.hs
new file mode 100644
--- /dev/null
+++ b/test/nat.hs
@@ -0,0 +1,16 @@
+{-# LANGUAGE TemplateHaskell #-}
+import Control.Applicative
+import Language.Haskell.TH
+import System.Exit
+
+import TestNat
+
+
+main :: IO ()
+main = do
+  plus  <- sequence $(listE (testAdd <$> [0..8] <*> [0..8]))
+  minus <- sequence $(listE [testSub n m | m <- [0..8], n <- [m..8]])
+  mult  <- sequence $(listE (testMul <$> [0..8] <*> [0..8]))
+  case and $ plus ++ minus ++ mult of
+    True  -> exitSuccess
+    False -> exitFailure
diff --git a/type-level-numbers.cabal b/type-level-numbers.cabal
--- a/type-level-numbers.cabal
+++ b/type-level-numbers.cabal
@@ -1,5 +1,5 @@
 Name:           type-level-numbers
-Version:        0.1.1.0
+Version:        0.1.1.1
 Synopsis:       
   Type level numbers implemented using type families.
 Description:
@@ -21,24 +21,8 @@
   .
   So far comparison of numbers, subtraction and multiplication of
   numbers are supported.
-  .
-  Changes in 0.1.1.0
-  .
-  * @withNat@, @withInt@, @SomeNat and @SomeInt@ added.
-  .
-  Changes in 0.1.0.3
-  .
-  * Fix build for GHC 7.4
-  .
-  Changes in 0.1.0.2:
-  .
-  * Fix URL in cabal file
-  .
-  Changes in 0.1.0.1:
-  .
-  * Workaround for GHC bug #4364 (Build failure on GHC 7.0)
 
-Cabal-Version:  >= 1.6
+Cabal-Version:  >= 1.8
 License:        BSD3
 License-File:   LICENSE
 Bug-reports:    https://github.com/bos/statistics/issues
@@ -47,6 +31,8 @@
 Homepage:       
 Category:       Type System
 Build-Type:     Simple
+extra-source-files:
+  ChangeLog
 
 source-repository head
   type:     hg
@@ -70,3 +56,23 @@
                    TypeLevel.Number.Nat.TH
                    TypeLevel.Number.Int.Types
                    TypeLevel.Util
+
+test-suite test-nat
+  type:           exitcode-stdio-1.0
+  hs-source-dirs: test
+  main-is:        nat.hs
+  other-modules:  TestNat
+  build-depends:
+    base,
+    template-haskell,
+    type-level-numbers
+
+test-suite test-int
+  type:           exitcode-stdio-1.0
+  hs-source-dirs: test
+  main-is:        int.hs
+  other-modules:  TestNat
+  build-depends:
+    base,
+    template-haskell,
+    type-level-numbers