Make sure Interval can be deepcopy-ed, fix #850

Author: aploium

src/pendulum/interval.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import copy
 import operator
 
 from datetime import date
@@ -453,3 +454,10 @@ def __eq__(self, other: object) -> bool:
 
     def __ne__(self, other: object) -> bool:
         return not self.__eq__(other)
+
+    def __deepcopy__(self, memodict: dict[int, Self]) -> Self:
+        return self.__class__(
+            copy.deepcopy(self.start),
+            copy.deepcopy(self.end),
+            self._absolute,
+        )

tests/interval/test_behavior.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import pickle
+import copy
 
 from datetime import timedelta
 
@@ -65,3 +66,18 @@ def test_inequality():
 
     assert interval1 != interval2
     assert interval1 != interval3
+
+
+def test_deepcopy():
+    dt1 = pendulum.datetime(2016, 11, 18)
+    dt2 = pendulum.datetime(2016, 11, 20)
+
+    interval = dt2 - dt1
+
+    interval2 = copy.deepcopy(interval)
+
+    assert interval == interval2
+    # make sure it's a deep copy
+    assert interval is not interval2
+    assert interval.start is not interval2.start
+    assert interval.end is not interval2.end