From 1d0e39059360de832ff4aaf33e047aaebba1c720 Mon Sep 17 00:00:00 2001
From: mrkkrp <markkarpov@opmbx.org>
Date: Mon, 5 Oct 2015 00:10:59 +0600
Subject: [PATCH] =?UTF-8?q?fixed=20test=20for=20=E2=80=98Text.Megaparsec.C?=
 =?UTF-8?q?har.string'=E2=80=99?=
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Closes #52.

Also added one new test for that function. The test is courtesy of
Benjamin Kästner (@bkaestner).
---
 tests/Char.hs | 20 +++++++++++++++++---
 tests/Util.hs |  2 +-
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/tests/Char.hs b/tests/Char.hs
index 72ccefb..92baa32 100644
--- a/tests/Char.hs
+++ b/tests/Char.hs
@@ -79,7 +79,8 @@ tests = testGroup "Character parsers"
         , testProperty "noneOf"          prop_noneOf
         , testProperty "noneOf'"         prop_noneOf'
         , testProperty "string"          prop_string
-        , testProperty "string'"         prop_string' ]
+        , testProperty "string'"         prop_string'_0
+        , testProperty "string' (case)"  prop_string'_1 ]
 
 instance Arbitrary GeneralCategory where
   arbitrary = elements
@@ -238,8 +239,21 @@ prop_noneOf' a = checkChar (noneOf' a) (`notElemi` a) Nothing
 prop_string :: String -> String -> Property
 prop_string a = checkString (string a) a (==) (showToken a)
 
-prop_string' :: String -> String -> Property
-prop_string' a = checkString (string' a) a casei (showToken a)
+prop_string'_0 :: String -> String -> Property
+prop_string'_0 a = checkString (string' a) a casei (showToken a)
+
+-- | Randomly change the case in the given string.
+
+fuzzyCase :: String -> Gen String
+fuzzyCase s = do
+    b <- vector (length s)
+    return $ zipWith f s b
+  where f k True  = if isLower k then toUpper k else toLower k
+        f k False = k
+
+prop_string'_1 :: String -> Property
+prop_string'_1 a = forAll (fuzzyCase a) $ \s ->
+  checkString (string' a) a casei (showToken a) s
 
 -- | Case-insensitive equality test for characters.
 
diff --git a/tests/Util.hs b/tests/Util.hs
index e6cc461..1cb6f87 100644
--- a/tests/Util.hs
+++ b/tests/Util.hs
@@ -101,7 +101,7 @@ checkChar p f l' s = checkParser p r s
 checkString :: Parser String -> String -> (Char -> Char -> Bool)
             -> String -> String -> Property
 checkString p a' test l s' = checkParser p (w a' 0 s') s'
-  where w [] _ []    = Right a'
+  where w [] _ []    = Right s'
         w [] i (s:_) = posErr i s' [uneCh s, exEof]
         w _  0 []    = posErr 0 s' [uneEof, exSpec l]
         w _  i []    = posErr 0 s' [uneStr (take i s'), exSpec l]