Close #14180: Factorize code to convert a number of seconds to time_t, timeval or timespec

time.ctime(), gmtime(), time.localtime(), datetime.date.fromtimestamp(),
datetime.datetime.fromtimestamp() and datetime.datetime.utcfromtimestamp() now
raises an OverflowError, instead of a ValueError, if the timestamp does not fit
in time_t.

datetime.datetime.fromtimestamp() and datetime.datetime.utcfromtimestamp() now
round microseconds towards zero instead of rounding to nearest with ties going
away from zero.

1 files changed, 27 insertions, 7 deletions

diff --git a/Lib/test/datetimetester.py b/Lib/test/datetimetester.py
index 5c02b3a..6de29c5 100644
--- a/Lib/test/datetimetester.py
+++ b/Lib/test/datetimetester.py
@@ -977,7 +977,7 @@ class TestDate(HarmlessMixedComparison, unittest.TestCase):
         # exempt such platforms (provided they return reasonable
         # results!).
         for insane in -1e200, 1e200:
-            self.assertRaises(ValueError, self.theclass.fromtimestamp,
+            self.assertRaises(OverflowError, self.theclass.fromtimestamp,
                               insane)
 
     def test_today(self):
@@ -1736,12 +1736,32 @@ class TestDateTime(TestDate):
         self.verify_field_equality(expected, got)
 
     def test_microsecond_rounding(self):
-        # Test whether fromtimestamp "rounds up" floats that are less
-        # than 1/2 microsecond smaller than an integer.
         for fts in [self.theclass.fromtimestamp,
                     self.theclass.utcfromtimestamp]:
-            self.assertEqual(fts(0.9999999), fts(1))
-            self.assertEqual(fts(0.99999949).microsecond, 999999)
+            zero = fts(0)
+            self.assertEqual(zero.second, 0)
+            self.assertEqual(zero.microsecond, 0)
+            minus_one = fts(-1e-6)
+            self.assertEqual(minus_one.second, 59)
+            self.assertEqual(minus_one.microsecond, 999999)
+
+            t = fts(-1e-8)
+            self.assertEqual(t, minus_one)
+            t = fts(-9e-7)
+            self.assertEqual(t, minus_one)
+            t = fts(-1e-7)
+            self.assertEqual(t, minus_one)
+
+            t = fts(1e-7)
+            self.assertEqual(t, zero)
+            t = fts(9e-7)
+            self.assertEqual(t, zero)
+            t = fts(0.99999949)
+            self.assertEqual(t.second, 0)
+            self.assertEqual(t.microsecond, 999999)
+            t = fts(0.9999999)
+            self.assertEqual(t.second, 0)
+            self.assertEqual(t.microsecond, 999999)
 
     def test_insane_fromtimestamp(self):
         # It's possible that some platform maps time_t to double,
@@ -1749,7 +1769,7 @@ class TestDateTime(TestDate):
         # exempt such platforms (provided they return reasonable
         # results!).
         for insane in -1e200, 1e200:
-            self.assertRaises(ValueError, self.theclass.fromtimestamp,
+            self.assertRaises(OverflowError, self.theclass.fromtimestamp,
                               insane)
 
     def test_insane_utcfromtimestamp(self):
@@ -1758,7 +1778,7 @@ class TestDateTime(TestDate):
         # exempt such platforms (provided they return reasonable
         # results!).
         for insane in -1e200, 1e200:
-            self.assertRaises(ValueError, self.theclass.utcfromtimestamp,
+            self.assertRaises(OverflowError, self.theclass.utcfromtimestamp,
                               insane)
     @unittest.skipIf(sys.platform == "win32", "Windows doesn't accept negative timestamps")
     def test_negative_float_fromtimestamp(self):