diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -1,18 +1,9 @@
 # string-transform
 
 [![Build Status](https://travis-ci.org/ncaq/string-transform.svg?branch=master)](https://travis-ci.org/ncaq/string-transform)
-
-It is
-
-* `Prelude.String`
-* `Data.ByteString.ByteString`
-* `Data.ByteString.Lazy.ByteString`
-* `Data.Text.Text`
-* `Data.Text.Lazy.Text`
-
-transform wrapper.
+![Hackage](https://img.shields.io/hackage/v/string-transform.svg)
 
-It is **simple** and **easy**.
+simple and easy haskell string transform wrapper.
 
 # provide function
 
diff --git a/src/Data/String/Transform.hs b/src/Data/String/Transform.hs
--- a/src/Data/String/Transform.hs
+++ b/src/Data/String/Transform.hs
@@ -1,6 +1,8 @@
 {-# LANGUAGE FlexibleInstances    #-}
+{-# LANGUAGE IncoherentInstances  #-}
 {-# LANGUAGE Safe                 #-}
 {-# LANGUAGE TypeSynonymInstances #-}
+{-# LANGUAGE UndecidableInstances #-}
 module Data.String.Transform where
 
 import qualified Data.ByteString           as B
@@ -30,6 +32,9 @@
 instance ToString TL.Text where
     toString = TL.unpack
 
+instance Show a => ToString a where
+    toString = show
+
 class ToByteStringStrict a where
     toByteStringStrict :: a -> B.ByteString
 
@@ -48,6 +53,9 @@
 instance ToByteStringStrict TL.Text where
     toByteStringStrict = T.encodeUtf8 . TL.toStrict
 
+instance Show a => ToByteStringStrict a where
+    toByteStringStrict = toByteStringStrict . show
+
 class ToByteStringLazy a where
     toByteStringLazy :: a -> BL.ByteString
 
@@ -66,6 +74,9 @@
 instance ToByteStringLazy TL.Text where
     toByteStringLazy = TL.encodeUtf8
 
+instance Show a => ToByteStringLazy a where
+    toByteStringLazy = toByteStringLazy . show
+
 class ToTextStrict a where
     toTextStrict :: a -> T.Text
 
@@ -84,6 +95,9 @@
 instance ToTextStrict TL.Text where
     toTextStrict = TL.toStrict
 
+instance Show a => ToTextStrict a where
+    toTextStrict = toTextStrict . show
+
 class ToTextLazy a where
     toTextLazy :: a -> TL.Text
 
@@ -101,3 +115,6 @@
 
 instance ToTextLazy TL.Text where
     toTextLazy = id
+
+instance Show a => ToTextLazy a where
+    toTextLazy = toTextLazy . show
diff --git a/string-transform.cabal b/string-transform.cabal
--- a/string-transform.cabal
+++ b/string-transform.cabal
@@ -3,8 +3,8 @@
 -- see: https://github.com/sol/hpack
 
 name:           string-transform
-version:        0.0.1
-synopsis:       simple and easy haskell string transform
+version:        0.1.0
+synopsis:       simple and easy haskell string transform wrapper
 category:       Text
 homepage:       https://github.com/ncaq/string-transform#readme
 bug-reports:    https://github.com/ncaq/string-transform/issues
diff --git a/test/Main.hs b/test/Main.hs
--- a/test/Main.hs
+++ b/test/Main.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE ScopedTypeVariables #-}
 module Main (main) where
 
 import           Data.String.Transform
@@ -16,28 +17,25 @@
 
 smallCheckTest :: [TestTree]
 smallCheckTest =
-    [ testProperty "toByteStringStrict" prop_toByteStringStrict_toString
-    , testProperty "toByteStringLazy" prop_toByteStringLazy_toString
-    , testProperty "toTextStrict" prop_toTextStrict_toString
-    , testProperty "toTextLazy" prop_toTextLazy_toString
+    [ testProperty "s == toString (toByteStringStrict s)"
+        (\(s :: String) -> s == toString (toByteStringStrict s))
+    , testProperty "s == toString (toByteStringLazy s)"
+        (\(s :: String) -> s == toString (toByteStringLazy s))
+    , testProperty "s == toString (toTextStrict s)"
+        (\(s :: String) -> s == toString (toTextStrict s))
+    , testProperty "s == toString (toTextLazy s)"
+        (\(s :: String) -> s == toString (toTextLazy s))
+    , testProperty "a == b ⇔ toByteStringStrict a == toByteStringStrict b"
+        (\(a :: String) (b :: String) ->
+             let p = a == b
+                 q = toByteStringStrict a == toByteStringStrict b
+             in p == q)
     ]
 
 hunitTest :: [TestTree]
 hunitTest =
-    [ testCase "toByteStringStrict 日本語" case_japanese_toByteStrictStrict_toString
+    [ testCase "toString 1" (toString 1 @?= "1")
+    , testCase "toByteStringStrict 1" (toByteStringStrict 1 @?= toByteStringStrict "1")
+    , testCase "toTextStrict 1" (toTextStrict 1 @?= toTextStrict "1")
+    , testCase "toByteStringStrict 日本語" (toString (toByteStringStrict "日本語") @?= "日本語")
     ]
-
-prop_toByteStringStrict_toString :: String -> Bool
-prop_toByteStringStrict_toString string = string == toString (toByteStringStrict string)
-
-prop_toByteStringLazy_toString :: String -> Bool
-prop_toByteStringLazy_toString string = string == toString (toByteStringLazy string)
-
-prop_toTextStrict_toString :: String -> Bool
-prop_toTextStrict_toString string = string == toString (toTextStrict string)
-
-prop_toTextLazy_toString :: String -> Bool
-prop_toTextLazy_toString string = string == toString (toTextLazy string)
-
-case_japanese_toByteStrictStrict_toString :: Assertion
-case_japanese_toByteStrictStrict_toString = toString (toByteStringStrict "日本語") @?= "日本語"