bpo-31784: Implement PEP 564: add time.time_ns() (#3989)

Add new time functions:

* time.clock_gettime_ns()
* time.clock_settime_ns()
* time.monotonic_ns()
* time.perf_counter_ns()
* time.process_time_ns()
* time.time_ns()

Add new _PyTime functions:

* _PyTime_FromTimespec()
* _PyTime_FromNanosecondsObject()
* _PyTime_FromTimeval()

Other changes:

* Add also os.times() tests to test_os.
* pytime_fromtimeval() and pytime_fromtimeval() now return
  _PyTime_MAX or _PyTime_MIN on overflow, rather than undefined
  behaviour
* _PyTime_FromNanoseconds() parameter type changes from long long to
  _PyTime_t

1 files changed, 17 insertions, 0 deletions

diff --git a/Lib/test/test_os.py b/Lib/test/test_os.py
index eb73af51ac..4d57bfbf9a 100644
--- a/Lib/test/test_os.py
+++ b/Lib/test/test_os.py
@@ -3549,6 +3549,23 @@ class TestPEP519(unittest.TestCase):
         self.assertRaises(ZeroDivisionError, self.fspath,
                           _PathLike(ZeroDivisionError()))
 
+
+class TimesTests(unittest.TestCase):
+    def test_times(self):
+        times = os.times()
+        self.assertIsInstance(times, os.times_result)
+
+        for field in ('user', 'system', 'children_user', 'children_system',
+                      'elapsed'):
+            value = getattr(times, field)
+            self.assertIsInstance(value, float)
+
+        if os.name == 'nt':
+            self.assertEqual(times.children_user, 0)
+            self.assertEqual(times.children_system, 0)
+            self.assertEqual(times.elapsed, 0)
+
+
 # Only test if the C version is provided, otherwise TestPEP519 already tested
 # the pure Python implementation.
 if hasattr(os, "_fspath"):