Implement recognition of the transition for int_timestamp method (#296)

Author: redlickigrzegorz

pendulum/datetime.py

@@ -185,6 +185,11 @@ def float_timestamp(self):
     def int_timestamp(self):
         # Workaround needed to avoid inaccuracy
         # for far into the future datetimes
+        kwargs = {"tzinfo": self.tzinfo}
+
+        if _HAS_FOLD:
+            kwargs["fold"] = self.fold
+
         dt = datetime.datetime(
             self.year,
             self.month,
@@ -193,7 +198,7 @@ def int_timestamp(self):
             self.minute,
             self.second,
             self.microsecond,
-            tzinfo=self.tzinfo,
+            **kwargs
         )
 
         delta = dt - self._EPOCH

tests/datetime/test_getters.py

@@ -4,6 +4,7 @@
 
 from pendulum import DateTime
 from pendulum.tz import timezone
+from pendulum.utils._compat import _HAS_FOLD
 
 from ..conftest import assert_date, assert_time
 
@@ -92,6 +93,29 @@ def test_int_timestamp_accuracy():
     assert d.int_timestamp == 32527311790
 
 
+def test_timestamp_with_transition():
+    d_pre = pendulum.datetime(
+        2012, 10, 28, 2, 0, tz="Europe/Warsaw", dst_rule=pendulum.PRE_TRANSITION
+    )
+    d_post = pendulum.datetime(
+        2012, 10, 28, 2, 0, tz="Europe/Warsaw", dst_rule=pendulum.POST_TRANSITION
+    )
+
+    if _HAS_FOLD:
+        # the difference between the timestamps before and after is equal to one hour
+        assert d_post.timestamp() - d_pre.timestamp() == pendulum.SECONDS_PER_HOUR
+        assert d_post.float_timestamp - d_pre.float_timestamp == (
+            pendulum.SECONDS_PER_HOUR
+        )
+        assert d_post.int_timestamp - d_pre.int_timestamp == pendulum.SECONDS_PER_HOUR
+    else:
+        # when the transition is not recognizable
+        # then the difference should be equal to zero hours
+        assert d_post.timestamp() - d_pre.timestamp() == 0
+        assert d_post.float_timestamp - d_pre.float_timestamp == 0
+        assert d_post.int_timestamp - d_pre.int_timestamp == 0
+
+
 def test_age():
     d = pendulum.now()
     assert d.age == 0