diff --git a/src/Data/Int/Int24.hs b/src/Data/Int/Int24.hs
--- a/src/Data/Int/Int24.hs
+++ b/src/Data/Int/Int24.hs
@@ -164,7 +164,8 @@
     {-# INLINE shiftR #-}
     -- same as the default definition, but we want it inlined (#2376)
     x `shiftR`  i = x `shift`  (-i)
-    bit      = bitDefault
+    bit n                     = case bit n of
+        I32# x -> I24# (narrow24Int# x)
     testBit  = testBitDefault
     popCount = popCountDefault
 
diff --git a/src/Data/Word/Word24.hs b/src/Data/Word/Word24.hs
--- a/src/Data/Word/Word24.hs
+++ b/src/Data/Word/Word24.hs
@@ -124,7 +124,8 @@
       !(I# i'#) = i `mod` 24
   bitSize _                 = 24
   isSigned _                = False
-  bit                       = bitDefault
+  bit n                     = case bit n of
+      W32# x -> W24# (narrow24Word# x)
   testBit (W24# x) n        = testBit (W32# x) n
   popCount (W24# x)         = popCount (W32# x)
 
diff --git a/tests/testword24.hs b/tests/testword24.hs
--- a/tests/testword24.hs
+++ b/tests/testword24.hs
@@ -133,6 +133,9 @@
 prop_comp a = complement (complement a) == a
   where types = a :: Word24
 
+prop_bit_ident q (NonNegative j) k =
+    testBit (bit j `asTypeOf` q) k == (j == k)
+
 -- Word Storable properties
 prop_sizeOf a = sizeOf a == 3
   where types = a :: Word24
@@ -267,7 +270,8 @@
 -- ----------------------------------------
 -- tests
 tests = [
-  testGroup "Word24" [
+ testGroup "Word24"
+  [ testGroup "basic" [
     testProperty "add. identity" prop_addIdent
     ,testProperty "mult. identity" prop_multIdent
     ,testProperty "unsigned" prop_unsigned
@@ -280,7 +284,7 @@
     ,testProperty "signum" prop_signum
     ,testProperty "Real identity" prop_real
     ]
-  ,testGroup "Word24 Integral instance" [
+  ,testGroup "Integral instance" [
     testProperty  "quot" prop_quot
     ,testProperty "rem" prop_rem
     ,testProperty "div" prop_div
@@ -288,7 +292,7 @@
     ,testProperty "quotRem" prop_quotrem
     ,testProperty "divmod" prop_divmod
     ]
-  ,testGroup "Word24 Enum instance" [
+  ,testGroup "Enum instance" [
     testProperty "enum succ" prop_enum1
     ,testProperty "enum pred" prop_enum2
     ,testProperty "toEnum" prop_enum3
@@ -296,7 +300,7 @@
     ,testProperty "enumFromTo" prop_enum5
     ,testProperty "enumFromThen" prop_enum6
     ]
-  ,testGroup "Word24 binary instance" [
+  ,testGroup "Bits instance" [
     testProperty "binary and" prop_and
     ,testProperty "binary or" prop_or
     ,testProperty "binary xor" prop_xor
@@ -307,12 +311,15 @@
     ,testProperty "binary shiftR" prop_shiftR2
     ,testProperty "binary rotate" prop_rotate
     ,testProperty "binary complement" prop_comp
+    ,testProperty "bit/testBit" (prop_bit_ident (0::Word24))
     ]
-  ,testGroup "Word24 Storable instance" [
+  ,testGroup "Storable instance" [
     testProperty  "sizeOf Word24" prop_sizeOf
     ,testProperty "aligntment" prop_align
     ]
-  ,testGroup "Int24" [
+  ]
+ ,testGroup "Int24"
+  [testGroup "basic" [
     testProperty "add. identity" prop_addIdentI
     ,testProperty "mult. identity" prop_multIdentI
     ,testProperty "Int16/Int24 conversion" prop_smallerI
@@ -324,7 +331,7 @@
     ,testProperty "signum" prop_signumI
     ,testProperty "Real identity" prop_realI
     ]
-  ,testGroup "Int24 Integral instance" [
+  ,testGroup "Integral instance" [
     testProperty  "quot" prop_quotI
     ,testProperty "rem" prop_remI
     ,testProperty "div" prop_divI
@@ -332,7 +339,7 @@
     ,testProperty "quotRem" prop_quotremI
     ,testProperty "divmod" prop_divmodI
     ]
-  ,testGroup "Int24 Enum instance" [
+  ,testGroup "Enum instance" [
     testProperty "enum succ" prop_enum1I
     ,testProperty "enum pred" prop_enum2I
     ,testProperty "toEnum" prop_enum3I
@@ -340,7 +347,7 @@
     ,testProperty "enumFromTo" prop_enum5I
     ,testProperty "enumFromThen" prop_enum6I
     ]
-  ,testGroup "Int24 binary instance" [
+  ,testGroup "Bits instance" [
     testProperty "binary and" prop_andI
     ,testProperty "binary or" prop_orI
     ,testProperty "binary xor" prop_xorI
@@ -351,12 +358,14 @@
     ,testProperty "binary shiftR" prop_shiftR2I
     ,testProperty "binary rotate" prop_rotateI
     ,testProperty "binary complement" prop_compI
+    ,testProperty "bit/testBit" (prop_bit_ident (0::Int24))
     ]
-  ,testGroup "Int24 Storable instance" [
+  ,testGroup "Storable instance" [
     testProperty  "sizeOf Int24" prop_sizeOfI
     ,testProperty "aligntment" prop_alignI
     ]
   ]
+ ]
 
 -- ----------------------------------------
 -- entry point
diff --git a/word24.cabal b/word24.cabal
--- a/word24.cabal
+++ b/word24.cabal
@@ -1,5 +1,5 @@
 name:		word24
-version:        1.0.4
+version:        1.0.5
 synopsis:       24-bit word and int types for GHC
 description:	24-bit Word and Int data types.
 category:       Data
@@ -38,13 +38,13 @@
   type: exitcode-stdio-1.0
   main-is: testword24.hs
   hs-source-dirs: tests src
-  ghc-options:    -fhpc -hpcdir dist/hpc/mix/word24-1.0.4
+  ghc-options:    -fhpc -hpcdir dist/hpc/mix/word24-1.0.5
 
   build-depends:
     base,
     word24,
     QuickCheck                 >= 2 && < 3,
-    test-framework             >= 0.2 && < 0.7,
+    test-framework             >= 0.2 && < 0.9,
     test-framework-quickcheck2 >= 0.2 && < 0.7
 
 benchmark bench24