Fix 3307 on Windows

testsuite/tests/ghc-regress/lib/IO/3307.hs

@@ -25,18 +25,19 @@ main = do
     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.
+    -- The file is created with a UTF-8 file name as well, so this will only work in Windows or a
+    -- UTF-8 locale, or this string will be encoded in some non-UTF-8 way and won't match.
     putStrLn "Test 3"
     let file = "chinese-file-小说"
     print $ map ord file
     readFile file >>= 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.
+    -- Again, the file is created with UTF-8 contents, so we read it in that encoding.
+    -- Once again, on non-Windows this may fail in a non-UTF-8 locale because we could encode the valid
+    -- filename string into a useless non-UTF-8 byte sequence.
     putStrLn "Test 4"
-    str <- readFileAs fileSystemEncoding "chinese-name"
+    str <- readFileAs utf8 "chinese-name"
     let file = dropTrailingSpace str
     print $ map ord file
     readFile file >>= putStr

testsuite/tests/ghc-regress/lib/IO/Makefile

@@ -43,6 +43,6 @@ environment001-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
-	# The tests are run in a UTF-8 locale. We would test another one
-	# (like Big5) but GHC developers probably won't have it on their machines.
+	# The tests are run in whatever the default locale is. This is almost always UTF-8,
+	# but in cmd on Windows it will be the non-Unicode CP850 locale.
 	./3307 chinese-file-小说

testsuite/tests/ghc-regress/lib/IO/all.T

@@ -119,8 +119,7 @@ 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']),
-      if_platform('i386-unknown-mingw32', expect_broken(5253))],
+     [extra_clean(['chinese-file-小说', 'chinese-name'])],
      run_command,
      ['$MAKE -s --no-print-directory 3307-test'])
 test('4855', normal, compile_and_run, [''])