Tests for the PEP383 functionality and bugs it fixes

16 files changed, 277 insertions, 30 deletions

diff --git a/testsuite/tests/ghc-regress/lib/IO/3307.hs b/testsuite/tests/ghc-regress/lib/IO/3307.hs
new file mode 100644
index 0000000000..a39bfedf48
--- /dev/null
+++ b/testsuite/tests/ghc-regress/lib/IO/3307.hs
@@ -0,0 +1,38 @@
+import Control.Exception
+
+import System.Directory
+import System.Environment
+import System.IO
+
+import Data.Char
+import Data.List
+
+import GHC.IO.Encoding
+
+main = do
+    -- 1) A file name arriving via an argument
+    [file] <- getArgs
+    readFile file >>= putStr
+    
+    -- 2) A file name arriving via getDirectoryContents
+    [file] <- fmap (filter ("chinese-file-" `isPrefixOf`)) $ getDirectoryContents "."
+    readFile file >>= putStr
+    
+    -- 3) A file name occurring literally in the program
+    -- This will only work if we are in the UTF-8 locale since the file is created
+    -- on disk with a UTF-8 file name.
+    readFile "chinese-file-小说" >>= putStr
+    
+    -- 4) A file name arriving via another file.
+    -- In this case we have to override the default encoding
+    -- so we get surrogate bytes for non-decodable namse.
+    (readFileAs fileSystemEncoding "chinese-name" >>= (readFile . dropTrailingSpace)) >>= putStr
+
+readFileAs :: TextEncoding -> FilePath -> IO String
+readFileAs enc fp = do
+    h <- openFile fp ReadMode
+    hSetEncoding h enc
+    hGetContents h
+
+dropTrailingSpace :: String -> String
+dropTrailingSpace = reverse . dropWhile (not . isAlphaNum) . reverse
diff --git a/testsuite/tests/ghc-regress/lib/IO/3307.stdout b/testsuite/tests/ghc-regress/lib/IO/3307.stdout
new file mode 100644
index 0000000000..f807e104b7
--- /dev/null
+++ b/testsuite/tests/ghc-regress/lib/IO/3307.stdout
@@ -0,0 +1,4 @@
+Ni hao
+Ni hao
+Ni hao
+Ni hao
diff --git a/testsuite/tests/ghc-regress/lib/IO/4855.hs b/testsuite/tests/ghc-regress/lib/IO/4855.hs
new file mode 100644
index 0000000000..fa862aaf14
--- /dev/null
+++ b/testsuite/tests/ghc-regress/lib/IO/4855.hs
@@ -0,0 +1,3 @@
+import Debug.Trace
+
+main = trace "我爱我的电脑" $ return ()
\ No newline at end of file
diff --git a/testsuite/tests/ghc-regress/lib/IO/4855.stderr b/testsuite/tests/ghc-regress/lib/IO/4855.stderr
new file mode 100644
index 0000000000..558550e229
--- /dev/null
+++ b/testsuite/tests/ghc-regress/lib/IO/4855.stderr
@@ -0,0 +1 @@
+我爱我的电脑
diff --git a/testsuite/tests/ghc-regress/lib/IO/Makefile b/testsuite/tests/ghc-regress/lib/IO/Makefile
index 0ad81226e1..e433ad73f8 100644
--- a/testsuite/tests/ghc-regress/lib/IO/Makefile
+++ b/testsuite/tests/ghc-regress/lib/IO/Makefile
@@ -12,25 +12,37 @@ test.concio001.thr:
 
 # NB. utf8-test should *not* have a final newline.  The last char should be 'X'.
 utf16-test: utf8-test
-	iconv -f UTF8 -t UTF16 <utf8-test >utf16-test
+	iconv -f UTF-8 -t UTF-16 <utf8-test >utf16-test
 
 utf16le-test: utf8-test
-	iconv -f UTF8 -t UTF16LE <utf8-test >utf16le-test
+	iconv -f UTF-8 -t UTF-16LE <utf8-test >utf16le-test
 
 utf16be-test: utf8-test
-	iconv -f UTF8 -t UTF16BE <utf8-test >utf16be-test
+	iconv -f UTF-8 -t UTF-16BE <utf8-test >utf16be-test
 
 utf32-test: utf8-test
-	iconv -f UTF8 -t UTF32 <utf8-test >utf32-test
+	iconv -f UTF-8 -t UTF-32 <utf8-test >utf32-test
 
 utf32le-test: utf8-test
-	iconv -f UTF8 -t UTF32LE <utf8-test >utf32le-test
+	iconv -f UTF-8 -t UTF-32LE <utf8-test >utf32le-test
 
 utf32be-test: utf8-test
-	iconv -f UTF8 -t UTF32BE <utf8-test >utf32be-test
+	iconv -f UTF-8 -t UTF-32BE <utf8-test >utf32be-test
 
 utf8-bom-test: utf16-test
-	iconv -f UTF16LE -t UTF8 <utf16-test >utf8-bom-test
+	iconv -f UTF-16LE -t UTF-8 <utf16-test >utf8-bom-test
 
 hSetEncoding001.in : latin1 utf8-test utf16le-test utf16be-test utf16-test utf32le-test utf32be-test utf32-test utf8-bom-test
 	cat >$@ latin1 utf8-test utf16le-test utf16be-test utf16-test utf32-test utf32le-test utf32be-test utf8-bom-test
+
+environment001-test:
+	@"$(TEST_HC)" --make -fforce-recomp -v0 environment001.hs -o environment001 
+	@(sleep 1; echo x) | GHC_TEST=马克斯 ./environment001 说
+
+3307-test:
+	@"$(TEST_HC)" --make -fforce-recomp -v0 3307.hs -o 3307
+	echo Ni hao > chinese-file-小说
+	echo chinese-file-小说 > chinese-name
+	# Try a UTF-8 locale. I would test another one (like Big5) but GHC
+	# developers probably won't have it on their machines:
+	@(sleep 1; echo x) | LC_ALL=en_US.UTF-8 ./3307 chinese-file-小说
diff --git a/testsuite/tests/ghc-regress/lib/IO/all.T b/testsuite/tests/ghc-regress/lib/IO/all.T
index 140bc2a48a..d60446fefb 100644
--- a/testsuite/tests/ghc-regress/lib/IO/all.T
+++ b/testsuite/tests/ghc-regress/lib/IO/all.T
@@ -1,3 +1,4 @@
+# -*- coding: utf-8 -*-
 
 def expect_fail_if_windows(opts):
    f = if_platform('i386-unknown-mingw32', expect_fail);
@@ -117,6 +118,8 @@ test('concio001.thr', skip, run_command, ['$MAKE -s --no-print-directory test.co
 test('concio002', reqlib('process'), compile_and_run, [''])
 
 test('2122', extra_clean(['2122-test']), compile_and_run, [''])
+test('3307', extra_clean(['chinese-file-小说', 'chinese-name']), run_command, ['$MAKE -s --no-print-directory 3307-test'])
+test('4855', normal, compile_and_run, [''])
 
 test('hSetEncoding001',extra_run_opts('hSetEncoding001.in'), compile_and_run, [''])
 test('decodingerror001',normal, compile_and_run, [''])
@@ -150,6 +153,10 @@ test('encoding001',
            'encoding001.utf8.utf32le']), 
      compile_and_run, [''])
 
+test('encoding002', normal, compile_and_run, [''])
+
+test('environment001', extra_clean(['environment001']), run_command, ['$MAKE -s --no-print-directory environment001-test'])
+
 test('newline001', extra_clean(['newline001.out']), compile_and_run, [''])
 
 test('openTempFile001', normal, compile_and_run, [''])
diff --git a/testsuite/tests/ghc-regress/lib/IO/decodingerror001.stdout b/testsuite/tests/ghc-regress/lib/IO/decodingerror001.stdout
index 887a8ba0b3..21e5208c79 100644
--- a/testsuite/tests/ghc-regress/lib/IO/decodingerror001.stdout
+++ b/testsuite/tests/ghc-regress/lib/IO/decodingerror001.stdout
@@ -1,8 +1,8 @@
-UTF8 error:Left decodingerror001.in1: hGetChar: invalid argument (invalid UTF-8 byte sequence)
-UTF8 error:Left decodingerror001.in1: hGetChar: invalid argument (invalid UTF-8 byte sequence)
-UTF8 error:Left decodingerror001.in1: hGetChar: invalid argument (invalid UTF-8 byte sequence)
-UTF8 error:Left decodingerror001.in1: hGetChar: invalid argument (invalid UTF-8 byte sequence)
-UTF8 error:Left decodingerror001.in1: hGetChar: invalid argument (invalid UTF-8 byte sequence)
+UTF8 error:Left decodingerror001.in1: hGetChar: invalid argument (invalid byte sequence)
+UTF8 error:Left decodingerror001.in1: hGetChar: invalid argument (invalid byte sequence)
+UTF8 error:Left decodingerror001.in1: hGetChar: invalid argument (invalid byte sequence)
+UTF8 error:Left decodingerror001.in1: hGetChar: invalid argument (invalid byte sequence)
+UTF8 error:Left decodingerror001.in1: hGetChar: invalid argument (invalid byte sequence)
 UTF8 incomplete sequence at end:Left decodingerror001.in2: hGetChar: invalid argument (invalid byte sequence for this encoding)
 UTF8 incomplete sequence at end:Left decodingerror001.in2: hGetChar: invalid argument (invalid byte sequence for this encoding)
 UTF8 incomplete sequence at end:Left decodingerror001.in2: hGetChar: invalid argument (invalid byte sequence for this encoding)
diff --git a/testsuite/tests/ghc-regress/lib/IO/encoding002.hs b/testsuite/tests/ghc-regress/lib/IO/encoding002.hs
new file mode 100644
index 0000000000..7c6f81a72a
--- /dev/null
+++ b/testsuite/tests/ghc-regress/lib/IO/encoding002.hs
@@ -0,0 +1,67 @@
+import Control.Monad
+
+import System.IO
+import Control.Exception
+
+import Foreign.Marshal.Array
+import Foreign.Ptr
+
+import GHC.Foreign
+import GHC.IO.Encoding (TextEncoding, mkTextEncoding)
+
+import Data.Char
+import Data.Word
+
+import Prelude hiding (catch)
+
+
+decode :: TextEncoding -> [Word8] -> IO String
+decode enc xs = withArrayLen xs (\sz p -> peekCStringLen enc (castPtr p, sz)) `catch` \e -> return (show (e :: IOException))
+
+encode :: TextEncoding -> String -> IO [Word8]
+encode enc cs = withCStringLen enc cs (\(p, sz) -> peekArray sz (castPtr p)) `catch` \e -> return (const [] (e :: IOException))
+
+asc :: Char -> Word8
+asc = fromIntegral . ord
+
+families = [ ([asc 'H', asc 'i', 0xED, 0xB2, 0x80, asc '!'],
+              ["UTF-8",    "UTF-8//IGNORE",    "UTF-8//TRANSLIT",    "UTF-8//SURROGATE"])
+           , ([asc 'H', 0, asc 'i', 0, 0xFF, 0xDF, 0xFF, 0xDF, asc '!', 0],
+              ["UTF-16LE", "UTF-16LE//IGNORE", "UTF-16LE//TRANSLIT", "UTF-16LE//SURROGATE"])
+           , ([0, asc 'H', 0, asc 'i', 0xDF, 0xFF, 0xDF, 0xFF, 0, asc '!'],
+              ["UTF-16BE", "UTF-16BE//IGNORE", "UTF-16BE//TRANSLIT", "UTF-16BE//SURROGATE"])
+           , ([asc 'H', 0, 0, 0, asc 'i', 0, 0, 0, 0xED, 0xB2, 0x80, 0, asc '!', 0, 0, 0],
+              ["UTF-32LE", "UTF-32LE//IGNORE", "UTF-32LE//TRANSLIT", "UTF-32LE//SURROGATE"])
+           , ([0, 0, 0, asc 'H', 0, 0, 0, asc 'i', 0, 0x80, 0xB2, 0xED, 0, 0, 0, asc '!'],
+              ["UTF-32BE", "UTF-32BE//IGNORE", "UTF-32BE//TRANSLIT", "UTF-32BE//SURROGATE"])
+           ]
+
+main = do
+  surrogate_enc <- mkTextEncoding "UTF-8//SURROGATE"
+    
+  -- Test that invalid input is correctly roundtripped as surrogates
+  -- This only works for the UTF-8 UTF since it is the only UTF which
+  -- is an ASCII superset.
+  putStrLn $ "== UTF-8: roundtripping"
+  let invalid_bytes = [asc 'H', asc 'i', 0xED, 0xB2, 0x80, asc '!']
+  surrogates <- decode surrogate_enc invalid_bytes
+  invalid_bytes' <- encode surrogate_enc surrogates
+  print invalid_bytes
+  print surrogates
+  print invalid_bytes'
+  print (invalid_bytes == invalid_bytes')
+  putStrLn ""
+  
+  forM families $ \(invalid_bytes, enc_names) -> do
+    encs <- mapM mkTextEncoding enc_names
+    let name = head enc_names
+    
+    -- How we deal with decoding errors in the various modes:
+    putStrLn $ "== " ++ name ++ ": decoding"
+    forM encs $ \enc -> decode enc invalid_bytes >>= print
+    
+    -- How about encoding errors, particularly those from embedded surrogates?
+    putStrLn $ "== " ++ name ++ ": encoding"
+    forM encs $ \enc -> encode enc "Hi\xDC80!" >>= print
+    
+    putStrLn ""
diff --git a/testsuite/tests/ghc-regress/lib/IO/encoding002.stdout b/testsuite/tests/ghc-regress/lib/IO/encoding002.stdout
new file mode 100644
index 0000000000..0cc885baa0
--- /dev/null
+++ b/testsuite/tests/ghc-regress/lib/IO/encoding002.stdout
@@ -0,0 +1,61 @@
+== UTF-8: roundtripping
+[72,105,237,178,128,33]
+"Hi\56557\56498\56448!"
+[72,105,237,178,128,33]
+True
+
+== UTF-8: decoding
+"recoverDecode: invalid argument (invalid byte sequence)"
+"Hi!"
+"Hi\65533\65533\65533!"
+"Hi\56557\56498\56448!"
+== UTF-8: encoding
+[]
+[72,105,33]
+[72,105,63,33]
+[72,105,128,33]
+
+== UTF-16LE: decoding
+"recoverDecode: invalid argument (invalid byte sequence)"
+"Hi\65503\8671"
+"Hi\65533\65503\8671\65533"
+"Hi\56575\65503\8671\NUL"
+== UTF-16LE: encoding
+[]
+[72,0,105,0,33,0]
+[72,0,105,0,63,0,33,0]
+[72,0,105,0,128,33,0]
+
+== UTF-16BE: decoding
+"recoverDecode: invalid argument (invalid byte sequence)"
+"Hi\65503\65280"
+"Hi\65533\65503\65280\65533"
+"Hi\56543\65503\65280!"
+== UTF-16BE: encoding
+[]
+[0,72,0,105,0,33]
+[0,72,0,105,0,63,0,33]
+[0,72,0,105,128,0,33]
+
+== UTF-32LE: decoding
+"recoverDecode: invalid argument (invalid byte sequence)"
+"Hi\8448"
+"Hi\65533\65533\65533\8448\65533"
+"Hi\56557\56498\56448\8448\NUL"
+== UTF-32LE: encoding
+[]
+[72,0,0,0,105,0,0,0,33,0,0,0]
+[72,0,0,0,105,0,0,0,63,0,0,0,33,0,0,0]
+[72,0,0,0,105,0,0,0,128,33,0,0,0]
+
+== UTF-32BE: decoding
+"recoverDecode: invalid argument (invalid byte sequence)"
+"Hi!"
+"Hi\65533\65533\65533\65533!"
+"Hi\NUL\56448\56498\56557!"
+== UTF-32BE: encoding
+[]
+[0,0,0,72,0,0,0,105,0,0,0,33]
+[0,0,0,72,0,0,0,105,0,0,0,63,0,0,0,33]
+[0,0,0,72,0,0,0,105,128,0,0,0,33]
+
diff --git a/testsuite/tests/ghc-regress/lib/IO/encodingerror001.stdout b/testsuite/tests/ghc-regress/lib/IO/encodingerror001.stdout
index 23718da4b2..7406cd9168 100644
--- a/testsuite/tests/ghc-regress/lib/IO/encodingerror001.stdout
+++ b/testsuite/tests/ghc-regress/lib/IO/encodingerror001.stdout
@@ -1,36 +1,36 @@
 test 1
-Caught <stdout>: hPutChar: invalid argument (character is out of range for this encoding) while trying to write "\283\n"
+Caught <stdout>: hPutChar: invalid argument (invalid character) while trying to write "\283\n"
 test 2
-HCaught <stdout>: hPutChar: invalid argument (character is out of range for this encoding) while trying to write "H\941llo\n"
+HCaught <stdout>: hPutChar: invalid argument (invalid character) while trying to write "H\941llo\n"
 test 3
-Hello Caught <stdout>: hPutChar: invalid argument (character is out of range for this encoding) while trying to write "Hello \945\946\947\n"
+Hello Caught <stdout>: hPutChar: invalid argument (invalid character) while trying to write "Hello \945\946\947\n"
 test 1
-Caught <stdout>: commitBuffer: invalid argument (character is out of range for this encoding) while trying to write "\283\n"
+Caught <stdout>: commitBuffer: invalid argument (invalid character) while trying to write "\283\n"
 test 2
-HCaught <stdout>: commitBuffer: invalid argument (character is out of range for this encoding) while trying to write "H\941llo\n"
+HCaught <stdout>: commitBuffer: invalid argument (invalid character) while trying to write "H\941llo\n"
 test 3
-Hello Caught <stdout>: commitBuffer: invalid argument (character is out of range for this encoding) while trying to write "Hello \945\946\947\n"
+Hello Caught <stdout>: commitBuffer: invalid argument (invalid character) while trying to write "Hello \945\946\947\n"
 test 1
-Caught <stdout>: commitBuffer: invalid argument (character is out of range for this encoding) while trying to write "\283\n"
+Caught <stdout>: commitBuffer: invalid argument (invalid character) while trying to write "\283\n"
 test 2
-HCaught <stdout>: commitBuffer: invalid argument (character is out of range for this encoding) while trying to write "H\941llo\n"
+HCaught <stdout>: commitBuffer: invalid argument (invalid character) while trying to write "H\941llo\n"
 test 3
-Hello Caught <stdout>: commitBuffer: invalid argument (character is out of range for this encoding) while trying to write "Hello \945\946\947\n"
+Hello Caught <stdout>: commitBuffer: invalid argument (invalid character) while trying to write "Hello \945\946\947\n"
 test 1
-Caught <stdout>: commitBuffer: invalid argument (character is out of range for this encoding) while trying to write "\283\n"
+Caught <stdout>: commitBuffer: invalid argument (invalid character) while trying to write "\283\n"
 test 2
-HCaught <stdout>: commitBuffer: invalid argument (character is out of range for this encoding) while trying to write "H\941llo\n"
+HCaught <stdout>: commitBuffer: invalid argument (invalid character) while trying to write "H\941llo\n"
 test 3
-Hello Caught <stdout>: commitBuffer: invalid argument (character is out of range for this encoding) while trying to write "Hello \945\946\947\n"
+Hello Caught <stdout>: commitBuffer: invalid argument (invalid character) while trying to write "Hello \945\946\947\n"
 test 1
-Caught <stdout>: commitBuffer: invalid argument (character is out of range for this encoding) while trying to write "\283\n"
+Caught <stdout>: commitBuffer: invalid argument (invalid character) while trying to write "\283\n"
 test 2
-HCaught <stdout>: commitBuffer: invalid argument (character is out of range for this encoding) while trying to write "H\941llo\n"
+HCaught <stdout>: commitBuffer: invalid argument (invalid character) while trying to write "H\941llo\n"
 test 3
-Hello Caught <stdout>: commitBuffer: invalid argument (character is out of range for this encoding) while trying to write "Hello \945\946\947\n"
+Hello Caught <stdout>: commitBuffer: invalid argument (invalid character) while trying to write "Hello \945\946\947\n"
 test 1
-Caught <stdout>: commitBuffer: invalid argument (character is out of range for this encoding) while trying to write "\283\n"
+Caught <stdout>: commitBuffer: invalid argument (invalid character) while trying to write "\283\n"
 test 2
-HCaught <stdout>: commitBuffer: invalid argument (character is out of range for this encoding) while trying to write "H\941llo\n"
+HCaught <stdout>: commitBuffer: invalid argument (invalid character) while trying to write "H\941llo\n"
 test 3
-Hello Caught <stdout>: commitBuffer: invalid argument (character is out of range for this encoding) while trying to write "Hello \945\946\947\n"
+Hello Caught <stdout>: commitBuffer: invalid argument (invalid character) while trying to write "Hello \945\946\947\n"
diff --git a/testsuite/tests/ghc-regress/lib/IO/environment001.hs b/testsuite/tests/ghc-regress/lib/IO/environment001.hs
new file mode 100644
index 0000000000..dbdaa2306b
--- /dev/null
+++ b/testsuite/tests/ghc-regress/lib/IO/environment001.hs
@@ -0,0 +1,16 @@
+import System.Environment
+
+main = do
+    var0 <- getEnv "GHC_TEST"
+    putStrLn var0
+    -- The length proves that we actually decoded it properly, not just read it
+    -- in as latin1 or something (#3308, #3307)
+    print (length var0)
+    
+    [arg0] <- getArgs
+    putStrLn arg0
+    print (length arg0)
+    
+    [arg1] <- withArgs ["你好!"] getArgs
+    putStrLn arg1
+    print (length arg1)
diff --git a/testsuite/tests/ghc-regress/lib/IO/environment001.stdout b/testsuite/tests/ghc-regress/lib/IO/environment001.stdout
new file mode 100644
index 0000000000..16299db556
--- /dev/null
+++ b/testsuite/tests/ghc-regress/lib/IO/environment001.stdout
@@ -0,0 +1,6 @@
+马克斯
+3
+说
+1
+你好!
+3
diff --git a/testsuite/tests/ghc-regress/lib/should_run/4006.hs b/testsuite/tests/ghc-regress/lib/should_run/4006.hs
new file mode 100644
index 0000000000..ea5c1ac458
--- /dev/null
+++ b/testsuite/tests/ghc-regress/lib/should_run/4006.hs
@@ -0,0 +1,8 @@
+import System.Process
+
+testUnicode :: String -> IO String
+testUnicode str = init `fmap` (readProcess "echo" [str] "")
+
+main = do
+    testUnicode "It works here" >>= putStrLn
+    testUnicode "А здесь сломалось" >>= putStrLn
diff --git a/testsuite/tests/ghc-regress/lib/should_run/4006.stdout b/testsuite/tests/ghc-regress/lib/should_run/4006.stdout
new file mode 100644
index 0000000000..9db8a8ced2
--- /dev/null
+++ b/testsuite/tests/ghc-regress/lib/should_run/4006.stdout
@@ -0,0 +1,2 @@
+It works here
+А здесь сломалось
diff --git a/testsuite/tests/ghc-regress/lib/should_run/all.T b/testsuite/tests/ghc-regress/lib/should_run/all.T
index 874e034904..388ad043ed 100644
--- a/testsuite/tests/ghc-regress/lib/should_run/all.T
+++ b/testsuite/tests/ghc-regress/lib/should_run/all.T
@@ -3,6 +3,8 @@ test('array001', 	normal, compile_and_run, [''])
 test('char001', 	normal, compile_and_run, [''])
 test('char002', 	normal, compile_and_run, [''])
 
+test('cstring001', 	normal, compile_and_run, [''])
+
 test('length001',
      # This fails without -O, as it relies on a RULE being applied
      expect_fail_for(['normal', 'threaded1', 'llvm']),
@@ -54,3 +56,5 @@ test('stableptr004', extra_run_opts('+RTS -K4m -RTS'), compile_and_run, [''])
 test('stableptr005', normal, compile_and_run, [''])
 
 test('weak001', normal, compile_and_run, [''])
+
+test('4006',		normal, compile_and_run, [''])
diff --git a/testsuite/tests/ghc-regress/lib/should_run/cstring001.hs b/testsuite/tests/ghc-regress/lib/should_run/cstring001.hs
new file mode 100644
index 0000000000..38d0d25db2
--- /dev/null
+++ b/testsuite/tests/ghc-regress/lib/should_run/cstring001.hs
@@ -0,0 +1,18 @@
+import Control.Monad
+import Foreign.C.String
+
+test_strings = ["Hello World", replicate 10000 'a']
+
+assertEqual :: (Eq a, Show a) => a -> a -> IO ()
+assertEqual x y = if x == y then return () else error $ "assertEqual: " ++ show x ++ " /= " ++ show y
+
+main = do
+    -- Try roundtripping some ASCII strings through the locale encoding
+    forM test_strings $ \try_str -> do
+        got_str <- withCString try_str peekCString
+        got_str `assertEqual` try_str
+
+    -- Try roundtripping some ASCII strings with lengths through the locale encoding
+    forM test_strings $ \try_str -> do
+        got_str <- withCStringLen try_str peekCStringLen
+        got_str `assertEqual` try_str