From 7d2f55ce07c251a7a58b52d6f8bd1d280b345437 Mon Sep 17 00:00:00 2001
From: Daniel Wagner <daniel@wagner-home.com>
Date: Mon, 3 Dec 2012 15:36:47 -0800
Subject: [PATCH] add a tool for generating regression tests before you start
 hacking on the implementation of an encoding

Ignore-this: d1f08ea3737455b87aa9828b88763d1f

darcs-hash:20121203233647-76d51-a289254906f15e21b147294bfa0d5b37efde2854
---
 tests/GenerateRegressionTests.hs | 40 ++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)
 create mode 100644 tests/GenerateRegressionTests.hs

diff --git a/tests/GenerateRegressionTests.hs b/tests/GenerateRegressionTests.hs
new file mode 100644
index 0000000..80c35ba
--- /dev/null
+++ b/tests/GenerateRegressionTests.hs
@@ -0,0 +1,40 @@
+{-# LANGUAGE NoMonomorphismRestriction #-}
+import Control.Monad
+import Data.ByteString (pack)
+import Data.Encoding
+import System.Random
+
+-- for example:
+import Data.Encoding.ISO2022JP
+main = generate ISO2022JP
+-- end example
+
+randomRepeat f max = randomRIO (0, max) >>= flip replicateM f
+randomString = randomRepeat randomIO
+randomGoodString = randomRepeat . randomGoodChar
+randomGoodChar f = let
+	good = filter f [minBound..maxBound]
+	n    = length good
+	in do
+	i <- randomRIO (0, n-1)
+	return (good !! i)
+
+generate enc = do
+	let filename = show enc ++ ".regression"
+	    randomGood = randomGoodString (encodeable enc)
+	shortMixedEnc <- replicateM  300 (randomString   10)
+	shortGoodEnc  <- replicateM   30 (randomGood     10)
+	longMixedEnc  <- replicateM  300 (randomString 1000)
+	longGoodEnc   <- replicateM 3000 (randomGood   1000)
+	shortDec      <- replicateM  300 (randomString   10)
+	longDec       <- replicateM 3000 (randomString 1000)
+	writeFile filename (show
+		[ (s, encodeStrictByteStringExplicit enc s)
+		| ss <- [shortMixedEnc, shortGoodEnc, longMixedEnc, longGoodEnc]
+		, s <- ss
+		] ++ "\n")
+	appendFile filename (show
+		[ (bs, decodeStrictByteStringExplicit enc (pack bs))
+		| bss <- [shortDec, longDec]
+		, bs <- bss
+		] ++ "\n")