Issue #23517: Add "half up" rounding mode to the _PyTime API

1 files changed, 61 insertions, 3 deletions

diff --git a/Lib/test/test_time.py b/Lib/test/test_time.py
index 6334e022e0..ed20470912 100644
--- a/Lib/test/test_time.py
+++ b/Lib/test/test_time.py
@@ -30,8 +30,11 @@ class _PyTime(enum.IntEnum):
     ROUND_FLOOR = 0
     # Round towards infinity (+inf)
     ROUND_CEILING = 1
+    # Round to nearest with ties going away from zero
+    ROUND_HALF_UP = 2
 
-ALL_ROUNDING_METHODS = (_PyTime.ROUND_FLOOR, _PyTime.ROUND_CEILING)
+ALL_ROUNDING_METHODS = (_PyTime.ROUND_FLOOR, _PyTime.ROUND_CEILING,
+                        _PyTime.ROUND_HALF_UP)
 
 
 class TimeTestCase(unittest.TestCase):
@@ -753,11 +756,11 @@ class TestPyTime_t(unittest.TestCase):
                 (123.0, 123 * SEC_TO_NS),
                 (-7.0, -7 * SEC_TO_NS),
 
-                # nanosecond are kept for value <= 2^23 seconds
+                # nanosecond are kept for value <= 2^23 seconds,
+                # except 2**23-1e-9 with HALF_UP
                 (2**22 - 1e-9,  4194303999999999),
                 (2**22,         4194304000000000),
                 (2**22 + 1e-9,  4194304000000001),
-                (2**23 - 1e-9,  8388607999999999),
                 (2**23,         8388608000000000),
 
                 # start loosing precision for value > 2^23 seconds
@@ -790,24 +793,36 @@ class TestPyTime_t(unittest.TestCase):
         # Conversion giving different results depending on the rounding method
         FLOOR = _PyTime.ROUND_FLOOR
         CEILING = _PyTime.ROUND_CEILING
+        HALF_UP =  _PyTime.ROUND_HALF_UP
         for obj, ts, rnd in (
             # close to zero
             ( 1e-10,  0, FLOOR),
             ( 1e-10,  1, CEILING),
+            ( 1e-10,  0, HALF_UP),
             (-1e-10, -1, FLOOR),
             (-1e-10,  0, CEILING),
+            (-1e-10,  0, HALF_UP),
 
             # test rounding of the last nanosecond
             ( 1.1234567899,  1123456789, FLOOR),
             ( 1.1234567899,  1123456790, CEILING),
+            ( 1.1234567899,  1123456790, HALF_UP),
             (-1.1234567899, -1123456790, FLOOR),
             (-1.1234567899, -1123456789, CEILING),
+            (-1.1234567899, -1123456790, HALF_UP),
 
             # close to 1 second
             ( 0.9999999999,   999999999, FLOOR),
             ( 0.9999999999,  1000000000, CEILING),
+            ( 0.9999999999,  1000000000, HALF_UP),
             (-0.9999999999, -1000000000, FLOOR),
             (-0.9999999999,  -999999999, CEILING),
+            (-0.9999999999, -1000000000, HALF_UP),
+
+            # close to 2^23 seconds
+            (2**23 - 1e-9,  8388607999999999, FLOOR),
+            (2**23 - 1e-9,  8388607999999999, CEILING),
+            (2**23 - 1e-9,  8388608000000000, HALF_UP),
         ):
             with self.subTest(obj=obj, round=rnd, timestamp=ts):
                 self.assertEqual(PyTime_FromSecondsObject(obj, rnd), ts)
@@ -875,18 +890,33 @@ class TestPyTime_t(unittest.TestCase):
 
         FLOOR = _PyTime.ROUND_FLOOR
         CEILING = _PyTime.ROUND_CEILING
+        HALF_UP = _PyTime.ROUND_HALF_UP
         for ns, tv, rnd in (
             # nanoseconds
             (1, (0, 0), FLOOR),
             (1, (0, 1), CEILING),
+            (1, (0, 0), HALF_UP),
             (-1, (-1, 999999), FLOOR),
             (-1, (0, 0), CEILING),
+            (-1, (0, 0), HALF_UP),
 
             # seconds + nanoseconds
             (1234567001, (1, 234567), FLOOR),
             (1234567001, (1, 234568), CEILING),
+            (1234567001, (1, 234567), HALF_UP),
             (-1234567001, (-2, 765432), FLOOR),
             (-1234567001, (-2, 765433), CEILING),
+            (-1234567001, (-2, 765433), HALF_UP),
+
+            # half up
+            (499, (0, 0), HALF_UP),
+            (500, (0, 1), HALF_UP),
+            (501, (0, 1), HALF_UP),
+            (999, (0, 1), HALF_UP),
+            (-499, (0, 0), HALF_UP),
+            (-500, (0, 0), HALF_UP),
+            (-501, (-1, 999999), HALF_UP),
+            (-999, (-1, 999999), HALF_UP),
         ):
             with self.subTest(nanoseconds=ns, timeval=tv, round=rnd):
                 self.assertEqual(PyTime_AsTimeval(ns, rnd), tv)
@@ -929,18 +959,33 @@ class TestPyTime_t(unittest.TestCase):
 
         FLOOR = _PyTime.ROUND_FLOOR
         CEILING = _PyTime.ROUND_CEILING
+        HALF_UP = _PyTime.ROUND_HALF_UP
         for ns, ms, rnd in (
             # nanoseconds
             (1, 0, FLOOR),
             (1, 1, CEILING),
+            (1, 0, HALF_UP),
             (-1, 0, FLOOR),
             (-1, -1, CEILING),
+            (-1, 0, HALF_UP),
 
             # seconds + nanoseconds
             (1234 * MS_TO_NS + 1, 1234, FLOOR),
             (1234 * MS_TO_NS + 1, 1235, CEILING),
+            (1234 * MS_TO_NS + 1, 1234, HALF_UP),
             (-1234 * MS_TO_NS - 1, -1234, FLOOR),
             (-1234 * MS_TO_NS - 1, -1235, CEILING),
+            (-1234 * MS_TO_NS - 1, -1234, HALF_UP),
+
+            # half up
+            (499999, 0, HALF_UP),
+            (499999, 0, HALF_UP),
+            (500000, 1, HALF_UP),
+            (999999, 1, HALF_UP),
+            (-499999, 0, HALF_UP),
+            (-500000, -1, HALF_UP),
+            (-500001, -1, HALF_UP),
+            (-999999, -1, HALF_UP),
         ):
             with self.subTest(nanoseconds=ns, milliseconds=ms, round=rnd):
                 self.assertEqual(PyTime_AsMilliseconds(ns, rnd), ms)
@@ -966,18 +1011,31 @@ class TestPyTime_t(unittest.TestCase):
 
         FLOOR = _PyTime.ROUND_FLOOR
         CEILING = _PyTime.ROUND_CEILING
+        HALF_UP = _PyTime.ROUND_HALF_UP
         for ns, ms, rnd in (
             # nanoseconds
             (1, 0, FLOOR),
             (1, 1, CEILING),
+            (1, 0, HALF_UP),
             (-1, 0, FLOOR),
             (-1, -1, CEILING),
+            (-1, 0, HALF_UP),
 
             # seconds + nanoseconds
             (1234 * US_TO_NS + 1, 1234, FLOOR),
             (1234 * US_TO_NS + 1, 1235, CEILING),
+            (1234 * US_TO_NS + 1, 1234, HALF_UP),
             (-1234 * US_TO_NS - 1, -1234, FLOOR),
             (-1234 * US_TO_NS - 1, -1235, CEILING),
+            (-1234 * US_TO_NS - 1, -1234, HALF_UP),
+
+            # half up
+            (1499, 1, HALF_UP),
+            (1500, 2, HALF_UP),
+            (1501, 2, HALF_UP),
+            (-1499, -1, HALF_UP),
+            (-1500, -2, HALF_UP),
+            (-1501, -2, HALF_UP),
         ):
             with self.subTest(nanoseconds=ns, milliseconds=ms, round=rnd):
                 self.assertEqual(PyTime_AsMicroseconds(ns, rnd), ms)