[libc++][test] Streaming out floating-point sys_time and local_time is bogus

[StephanTLavavej]

N4964 [time.clock.system.nonmembers]/1:

template<class charT, class traits, class Duration>
  basic_ostream<charT, traits>&
    operator<<(basic_ostream<charT, traits>& os, const sys_time<Duration>& tp);

Constraints: treat_as_floating_point_v<typename Duration::rep> is false, and Duration{1} < days{1} is true.

forbids:

llvm-project/libcxx/test/std/time/time.clock/time.clock.system/ostream.pass.cpp

Lines 93 to 98 in 002c54a

	assert(stream_c_locale<CharT>(std::chrono::sys_time<std::chrono::duration<float, std::ratio<1, 1>>>{
	std::chrono::duration<float, std::ratio<1, 1>>{123.456}}) == SV("1970-01-01 00:02:03"));
	assert(stream_c_locale<CharT>(std::chrono::sys_time<std::chrono::duration<double, std::ratio<1, 10>>>{
	std::chrono::duration<double, std::ratio<1, 10>>{123.456}}) == SV("1970-01-01 00:00:12.3"));
	assert(stream_c_locale<CharT>(std::chrono::sys_time<std::chrono::duration<long double, std::ratio<1, 100>>>{
	std::chrono::duration<long double, std::ratio<1, 100>>{123.456}}) == SV("1970-01-01 00:00:01.23"));

llvm-project/libcxx/test/std/time/time.clock/time.clock.system/ostream.pass.cpp

Lines 131 to 136 in 002c54a

	assert(stream_fr_FR_locale<CharT>(std::chrono::sys_time<std::chrono::duration<float, std::ratio<1, 1>>>{
	std::chrono::duration<float, std::ratio<1, 1>>{123.456}}) == SV("1970-01-01 00:02:03"));
	assert(stream_fr_FR_locale<CharT>(std::chrono::sys_time<std::chrono::duration<double, std::ratio<1, 10>>>{
	std::chrono::duration<double, std::ratio<1, 10>>{123.456}}) == SV("1970-01-01 00:00:12,3"));
	assert(stream_fr_FR_locale<CharT>(std::chrono::sys_time<std::chrono::duration<long double, std::ratio<1, 100>>>{
	std::chrono::duration<long double, std::ratio<1, 100>>{123.456}}) == SV("1970-01-01 00:00:01,23"));

---

And [time.clock.local]/2:

template<class charT, class traits, class Duration>
  basic_ostream<charT, traits>&
    operator<<(basic_ostream<charT, traits>& os, const local_time<Duration>& lt);

Effects: os << sys_time<Duration>{lt.time_since_epoch()};

forbids:

llvm-project/libcxx/test/std/time/time.clock/time.clock.local/ostream.pass.cpp

Lines 93 to 98 in 002c54a

	assert(stream_c_locale<CharT>(std::chrono::local_time<std::chrono::duration<float, std::ratio<1, 1>>>{
	std::chrono::duration<float, std::ratio<1, 1>>{123.456}}) == SV("1970-01-01 00:02:03"));
	assert(stream_c_locale<CharT>(std::chrono::local_time<std::chrono::duration<double, std::ratio<1, 10>>>{
	std::chrono::duration<double, std::ratio<1, 10>>{123.456}}) == SV("1970-01-01 00:00:12.3"));
	assert(stream_c_locale<CharT>(std::chrono::local_time<std::chrono::duration<long double, std::ratio<1, 100>>>{
	std::chrono::duration<long double, std::ratio<1, 100>>{123.456}}) == SV("1970-01-01 00:00:01.23"));

llvm-project/libcxx/test/std/time/time.clock/time.clock.local/ostream.pass.cpp

Lines 132 to 137 in 002c54a

	assert(stream_fr_FR_locale<CharT>(std::chrono::local_time<std::chrono::duration<float, std::ratio<1, 1>>>{
	std::chrono::duration<float, std::ratio<1, 1>>{123.456}}) == SV("1970-01-01 00:02:03"));
	assert(stream_fr_FR_locale<CharT>(std::chrono::local_time<std::chrono::duration<double, std::ratio<1, 10>>>{
	std::chrono::duration<double, std::ratio<1, 10>>{123.456}}) == SV("1970-01-01 00:00:12,3"));
	assert(stream_fr_FR_locale<CharT>(std::chrono::local_time<std::chrono::duration<long double, std::ratio<1, 100>>>{
	std::chrono::duration<long double, std::ratio<1, 100>>{123.456}}) == SV("1970-01-01 00:00:01,23"));

[mordante]

Thanks! I had a look and it seems I didn't implement the required constraint. So it's not just the test suite, the implementation has issues too.