[libcxx] [test] Skip timezone formatting tests on Windows

[mstorsjo]

Summary

While these tests do pass in the CI environment, they fail elsewhere.
On GitHub Action runners, they produce '+0000' instead of '-0000' for
the UTC offset, and on local machines, it outputs the UTC offset of
the local timezone.

[Mordante]

LGTM, thanks!

[mstorsjo]

Rebase to try to rerun CI

libcxx/test/std/time/time.syn/formatter.file_time.pass.cpp

#endif                                 // __APPLE__
   std::locale::global(std::locale::classic());
 }
 
 template <class CharT>
 static void test_valid_values_time_zone() {
 // The Apple CI gives %z='-0700'  %Ez='-0700' %Oz='-0700' %Z='UTC'
 // -0700 looks like the local time where the CI happens to recide, therefore
 // omit this test on Apple.
-#if !defined(__APPLE__)
+// The Windows CI gives %z='-0000', but on local machines set to a different
+// timezone, it gives e.g. %z='+0200'.
+#if !defined(__APPLE__) && !defined(_WIN32)
   using namespace std::literals::chrono_literals;
 
   constexpr std::basic_string_view<CharT> fmt  = SV("{:%%z='%z'%t%%Ez='%Ez'%t%%Oz='%Oz'%t%%Z='%Z'%n}");
   constexpr std::basic_string_view<CharT> lfmt = SV("{:L%%z='%z'%t%%Ez='%Ez'%t%%Oz='%Oz'%t%%Z='%Z'%n}");
 
   const std::locale loc(LOCALE_ja_JP_UTF_8);
   std::locale::global(std::locale(LOCALE_fr_FR_UTF_8));
 
 #  if defined(_AIX)
   // Non localized output using C-locale
   check(SV("%z='UTC'\t%Ez='UTC'\t%Oz='UTC'\t%Z='UTC'\n"),
         fmt,
         file_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
 
   // Use the global locale (fr_FR)
   check(SV("%z='UTC'\t%Ez='UTC'\t%Oz='UTC'\t%Z='UTC'\n"),
         lfmt,
         file_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
 
   // Use supplied locale (ja_JP). This locale has a different alternate.a
   check(loc,
         SV("%z='UTC'\t%Ez='UTC'\t%Oz='UTC'\t%Z='UTC'\n"),
         lfmt,
         file_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
-#  elif defined(_WIN32)    // defined(_AIX)
-  // Non localized output using C-locale
-  check(SV("%z='-0000'\t%Ez='-0000'\t%Oz='-0000'\t%Z='UTC'\n"),
-        fmt,
-        file_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
-
-  // Use the global locale (fr_FR)
-  check(SV("%z='-0000'\t%Ez='-0000'\t%Oz='-0000'\t%Z='UTC'\n"),
-        lfmt,
-        file_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
-
-  // Use supplied locale (ja_JP). This locale has a different alternate.a
-  check(loc,
-        SV("%z='-0000'\t%Ez='-0000'\t%Oz='-0000'\t%Z='UTC'\n"),
-        lfmt,
-        file_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
 #  else                    // defined(_AIX)
   // Non localized output using C-locale
   check(SV("%z='+0000'\t%Ez='+0000'\t%Oz='+0000'\t%Z='UTC'\n"),
         fmt,
         file_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
 
   // Use the global locale (fr_FR)
   check(SV("%z='+0000'\t%Ez='+0000'\t%Oz='+0000'\t%Z='UTC'\n"),
         lfmt,
         file_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
 
   // Use supplied locale (ja_JP). This locale has a different alternate.a
   check(loc,
         SV("%z='+0000'\t%Ez='+0000'\t%Oz='+〇'\t%Z='UTC'\n"),
         lfmt,
         file_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
 #  endif                   // defined(_AIX)
   std::locale::global(std::locale::classic());
-#endif // !defined(__APPLE__)
+#endif // !defined(__APPLE__) && !defined(_WIN32)
 }
 
 template <class CharT>
 static void test_valid_values() {
   test_valid_values_year<CharT>();
   test_valid_values_month<CharT>();
   test_valid_values_day<CharT>();
   test_valid_values_weekday<CharT>();

libcxx/test/std/time/time.syn/formatter.sys_time.pass.cpp

#endif                                             // __APPLE__
   std::locale::global(std::locale::classic());
 }
 
 template <class CharT>
 static void test_valid_values_time_zone() {
 // The Apple CI gives %z='-0700'  %Ez='-0700' %Oz='-0700' %Z='UTC'
 // -0700 looks like the local time where the CI happens to recide, therefore
 // omit this test on Apple.
-#if !defined(__APPLE__)
+// The Windows CI gives %z='-0000', but on local machines set to a different
+// timezone, it gives e.g. %z='+0200'.
+#if !defined(__APPLE__) && !defined(_WIN32)
   using namespace std::literals::chrono_literals;
 
   constexpr std::basic_string_view<CharT> fmt  = SV("{:%%z='%z'%t%%Ez='%Ez'%t%%Oz='%Oz'%t%%Z='%Z'%n}");
   constexpr std::basic_string_view<CharT> lfmt = SV("{:L%%z='%z'%t%%Ez='%Ez'%t%%Oz='%Oz'%t%%Z='%Z'%n}");
 
   const std::locale loc(LOCALE_ja_JP_UTF_8);
   std::locale::global(std::locale(LOCALE_fr_FR_UTF_8));
 
 #  if defined(_AIX)
   // Non localized output using C-locale
   check(SV("%z='UTC'\t%Ez='UTC'\t%Oz='UTC'\t%Z='UTC'\n"),
         fmt,
         std::chrono::sys_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
 
   // Use the global locale (fr_FR)
   check(SV("%z='UTC'\t%Ez='UTC'\t%Oz='UTC'\t%Z='UTC'\n"),
         lfmt,
         std::chrono::sys_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
 
   // Use supplied locale (ja_JP). This locale has a different alternate.a
   check(loc,
         SV("%z='UTC'\t%Ez='UTC'\t%Oz='UTC'\t%Z='UTC'\n"),
         lfmt,
         std::chrono::sys_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
-#  elif defined(_WIN32)                // defined(_AIX)
-  // Non localized output using C-locale
-  check(SV("%z='-0000'\t%Ez='-0000'\t%Oz='-0000'\t%Z='UTC'\n"),
-        fmt,
-        std::chrono::sys_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
-
-  // Use the global locale (fr_FR)
-  check(SV("%z='-0000'\t%Ez='-0000'\t%Oz='-0000'\t%Z='UTC'\n"),
-        lfmt,
-        std::chrono::sys_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
-
-  // Use supplied locale (ja_JP). This locale has a different alternate.a
-  check(loc,
-        SV("%z='-0000'\t%Ez='-0000'\t%Oz='-0000'\t%Z='UTC'\n"),
-        lfmt,
-        std::chrono::sys_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
 #  else                                // defined(_AIX)
   // Non localized output using C-locale
   check(SV("%z='+0000'\t%Ez='+0000'\t%Oz='+0000'\t%Z='UTC'\n"),
         fmt,
         std::chrono::sys_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
 
   // Use the global locale (fr_FR)
   check(SV("%z='+0000'\t%Ez='+0000'\t%Oz='+0000'\t%Z='UTC'\n"),
         lfmt,
         std::chrono::sys_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
 
   // Use supplied locale (ja_JP). This locale has a different alternate.a
   check(loc,
         SV("%z='+0000'\t%Ez='+0000'\t%Oz='+〇'\t%Z='UTC'\n"),
         lfmt,
         std::chrono::sys_seconds(0s)); // 00:00:00 UTC Thursday, 1 January 1970
 #  endif                               // defined(_AIX)
   std::locale::global(std::locale::classic());
-#endif // !defined(__APPLE__)
+#endif // !defined(__APPLE__) && !defined(_WIN32)
 }
 
 template <class CharT>
 static void test_valid_values() {
   test_valid_values_year<CharT>();
   test_valid_values_month<CharT>();
   test_valid_values_day<CharT>();
   test_valid_values_weekday<CharT>();