[v3-0-test] Persist EventsTimetable's description during serialization (#51203) (#51926)

(cherry picked from commit a150e70)

Co-authored-by: Kacper Muda <[email protected]>

Author: github-actions[bot]

airflow-core/src/airflow/timetables/events.py

@@ -62,7 +62,8 @@ def __init__(
         if description is None:
             if self.event_dates:
                 self.description = (
-                    f"{len(self.event_dates)} events between {self.event_dates[0]} and {self.event_dates[-1]}"
+                    f"{len(self.event_dates)} events between "
+                    f"{self.event_dates[0].isoformat(sep='T')} and {self.event_dates[-1].isoformat(sep='T')}"
                 )
             else:
                 self.description = "No events"
@@ -123,12 +124,17 @@ def serialize(self):
         return {
             "event_dates": [x.isoformat(sep="T") for x in self.event_dates],
             "restrict_to_events": self.restrict_to_events,
+            "description": self.description,
+            "_summary": self._summary,
         }
 
     @classmethod
     def deserialize(cls, data) -> Timetable:
-        return cls(
-            [pendulum.DateTime.fromisoformat(x) for x in data["event_dates"]],
-            data["restrict_to_events"],
+        time_table = cls(
+            event_dates=[pendulum.DateTime.fromisoformat(x) for x in data["event_dates"]],
+            restrict_to_events=data["restrict_to_events"],
             presorted=True,
+            description=data["description"],
         )
+        time_table._summary = data["_summary"]
+        return time_table

airflow-core/tests/unit/timetables/test_events_timetable.py

@@ -190,4 +190,33 @@ def test_serialize(unrestricted_timetable: Timetable):
             "2021-10-09T00:00:00+00:00",
         ],
         "restrict_to_events": False,
+        "_summary": "6 events",
+        "description": "6 events between 2021-09-06T00:00:00+00:00 and 2021-10-09T00:00:00+00:00",
     }
+
+
+def test_timetable_after_serialization_is_the_same():
+    description = "Example description"
+    timetable = EventsTimetable(
+        event_dates=EVENT_DATES, restrict_to_events=True, description=description, presorted=True
+    )
+    assert timetable.summary == description
+    assert timetable.description == description
+    assert timetable.event_dates == EVENT_DATES
+
+    deserialized: EventsTimetable = timetable.deserialize(timetable.serialize())
+    assert deserialized.summary == description
+    assert deserialized.description == description
+    assert deserialized.event_dates == EVENT_DATES
+
+
+def test_timetable_without_description_after_serialization_is_the_same():
+    timetable = EventsTimetable(event_dates=EVENT_DATES, presorted=True)
+    summary = f"{timetable.summary}"
+    description = f"{timetable.description}"
+    assert timetable.event_dates == EVENT_DATES
+
+    deserialized: EventsTimetable = timetable.deserialize(timetable.serialize())
+    assert deserialized.summary == summary
+    assert deserialized.description == description
+    assert deserialized.event_dates == EVENT_DATES