Make Timezone and FixedTimezone hashable

src/pendulum/tz/timezone.py

@@ -69,6 +69,9 @@ def __new__(cls, key: str) -> Self:
     def __eq__(self, other: object) -> bool:
         return isinstance(other, Timezone) and self.key == other.key
 
+    def __hash__(self) -> int:
+        return hash((Timezone, self.key))
+
     @property
     def name(self) -> str:
         return self.key
@@ -178,6 +181,9 @@ def __init__(self, offset: int, name: str | None = None) -> None:
     def __eq__(self, other: object) -> bool:
         return isinstance(other, FixedTimezone) and self._offset == other._offset
 
+    def __hash__(self) -> int:
+        return hash((FixedTimezone, self._offset))
+
     @property
     def name(self) -> str:
         return self._name

tests/tz/test_timezone.py

@@ -13,6 +13,7 @@
 from pendulum.tz import fixed_timezone
 from pendulum.tz.exceptions import AmbiguousTime
 from pendulum.tz.exceptions import NonExistingTime
+from pendulum.tz.timezone import FixedTimezone
 from tests.conftest import assert_datetime
 
 
@@ -47,6 +48,11 @@ def test_equality():
     assert timezone("Europe/Paris") != timezone("Europe/Berlin")
 
 
+def test_hash():
+    assert hash(timezone("Europe/Paris")) == hash(timezone("Europe/Paris"))
+    assert len({timezone("Europe/Paris"), timezone("Europe/Paris")}) == 1
+
+
 def test_skipped_time_with_pre_rule():
     dt = datetime(2013, 3, 31, 2, 30, 45, 123456, fold=0)
     tz = timezone("Europe/Paris")
@@ -409,6 +415,14 @@ def test_fixed_equality():
     assert fixed_timezone(19800) != fixed_timezone(19801)
 
 
+def test_fixed_hash():
+    assert hash(fixed_timezone(19800)) == hash(fixed_timezone(19800))
+    assert fixed_timezone(19800) == FixedTimezone(19800, name="custom"), (
+        "Pre-condition: name ignored for FixedTimezone"
+    )
+    assert len({fixed_timezone(19800), FixedTimezone(19800, name="custom")}) == 1
+
+
 def test_just_before_last_transition():
     tz = pendulum.timezone("Asia/Shanghai")
     dt = datetime(1991, 4, 20, 1, 49, 8, fold=0)