[libc++] Remove unique usage of the en_US locale in a test

[ldionne]

Summary

Just like we guard other tests with REQUIRES: locale.en_US.UTF-8, it makes sense to
guard this test for its usage of the en_US locale.

[ldionne]

I came across this in a different context, but please let me know if that doesn't make sense, I'm obviously not a locale expert.

[mstorsjo]

Looks reasonable to me!

[Mordante]

LGTM, but I would consider an alternate approach and not add this locale to features.py.

libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt.byname/ctor_char.pass.cpp

16

Looking at the test it doesn't really matter which locale is used. So I would suggest to use an existing locale in this patch instead, and update the commit title and message.

[ldionne]

Address comment.

libcxx/test/std/localization/locale.categories/category.ctype/locale.codecvt.byname/ctor_char.pass.cpp

 //===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 // <locale>
 
 // template <> class codecvt_byname<char, char, mbstate_t>
 
 // explicit codecvt_byname(const char* nm, size_t refs = 0);
 // explicit codecvt_byname(const string& nm, size_t refs = 0);
 
+// REQUIRES: locale.en_US.UTF-8
+
 #include <locale>
 #include <cassert>
 
 #include "test_macros.h"
 #include "platform_support.h"
 
 typedef std::codecvt_byname<char, char, std::mbstate_t> F;
 
public:
     ~my_facet() {--count;}
 };
 
 int my_facet::count = 0;
 
 int main(int, char**)
 {
     {
-        std::locale l(std::locale::classic(), new my_facet(LOCALE_en_US));
+        std::locale l(std::locale::classic(), new my_facet(LOCALE_en_US_UTF_8));
         assert(my_facet::count == 1);
     }
     assert(my_facet::count == 0);
     {
-        my_facet f(LOCALE_en_US, 1);
+        my_facet f(LOCALE_en_US_UTF_8, 1);
         assert(my_facet::count == 1);
         {
             std::locale l(std::locale::classic(), &f);
             assert(my_facet::count == 1);
         }
         assert(my_facet::count == 1);
     }
     assert(my_facet::count == 0);
     {
-        std::locale l(std::locale::classic(), new my_facet(std::string(LOCALE_en_US)));
+        std::locale l(std::locale::classic(), new my_facet(std::string(LOCALE_en_US_UTF_8)));
         assert(my_facet::count == 1);
     }
     assert(my_facet::count == 0);
     {
-        my_facet f(std::string(LOCALE_en_US), 1);
+        my_facet f(std::string(LOCALE_en_US_UTF_8), 1);
         assert(my_facet::count == 1);
         {
             std::locale l(std::locale::classic(), &f);
             assert(my_facet::count == 1);
         }
         assert(my_facet::count == 1);
     }
     assert(my_facet::count == 0);
 
   return 0;
 }

libcxx/test/support/platform_support.h

 //   - floating point number string output
 
 #ifndef PLATFORM_SUPPORT_H
 #define PLATFORM_SUPPORT_H
 
 #include "test_macros.h"
 
 // locale names
-#define LOCALE_en_US           "en_US"
 #define LOCALE_en_US_UTF_8     "en_US.UTF-8"
 #define LOCALE_fr_FR_UTF_8     "fr_FR.UTF-8"
 #ifdef __linux__
 #    define LOCALE_fr_CA_ISO8859_1 "fr_CA.ISO-8859-1"
 #    define LOCALE_cs_CZ_ISO8859_2 "cs_CZ.ISO-8859-2"
 #elif defined(_WIN32)
 #    define LOCALE_fr_CA_ISO8859_1 "fr-CA"
 #    define LOCALE_cs_CZ_ISO8859_2 "cs-CZ"