From 29d02c56f5cada4896ae00613ab15574b5d29746 Mon Sep 17 00:00:00 2001
From: Kirilishin Aleksei <avkirilishin@gmail.com>
Date: Sat, 9 Dec 2023 03:24:19 +0400
Subject: [PATCH] Add the empty timetable tests

---
 airflow/timetables/events.py              | 13 ++++++++-----
 tests/timetables/test_events_timetable.py | 15 +++++++++++++++
 2 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/airflow/timetables/events.py b/airflow/timetables/events.py
index 53d5019da4226..0edf1b101299c 100644
--- a/airflow/timetables/events.py
+++ b/airflow/timetables/events.py
@@ -58,10 +58,13 @@ def __init__(
             self.event_dates.sort()
         self.restrict_to_events = restrict_to_events
         if description is None:
-            self.description = (
-                f"{len(self.event_dates)} Events between {self.event_dates[0]} and {self.event_dates[-1]}"
-            )
-            self._summary = f"{len(self.event_dates)} Events"
+            if self.event_dates:
+                self.description = (
+                    f"{len(self.event_dates)} events between {self.event_dates[0]} and {self.event_dates[-1]}"
+                )
+            else:
+                self.description = "No events"
+            self._summary = f"{len(self.event_dates)} events"
         else:
             self._summary = description
             self.description = description
@@ -106,7 +109,7 @@ def next_dagrun_info(
 
     def infer_manual_data_interval(self, *, run_after: DateTime) -> DataInterval:
         # If Timetable not restricted to events, run for the time specified
-        if not self.restrict_to_events:
+        if not self.restrict_to_events or not self.event_dates:
             return DataInterval.exact(run_after)
 
         # If restricted to events, run for the most recent past event
diff --git a/tests/timetables/test_events_timetable.py b/tests/timetables/test_events_timetable.py
index 131a618de6b8d..39d1fd3431e34 100644
--- a/tests/timetables/test_events_timetable.py
+++ b/tests/timetables/test_events_timetable.py
@@ -161,3 +161,18 @@ def test_no_catchup_first_starts(
             restriction=TimeRestriction(earliest=START_DATE, latest=None, catchup=False),
         )
     assert next_info == expected_info
+
+
+def test_empty_timetable() -> None:
+    empty_timetable = EventsTimetable(event_dates=[])
+    next_info = empty_timetable.next_dagrun_info(
+        last_automated_data_interval=None,
+        restriction=TimeRestriction(earliest=START_DATE, latest=None, catchup=False),
+    )
+    assert next_info is None
+
+
+def test_empty_timetable_manual_run() -> None:
+    empty_timetable = EventsTimetable(event_dates=[])
+    manual_run_data_interval = empty_timetable.infer_manual_data_interval(run_after=START_DATE)
+    assert manual_run_data_interval == DataInterval(start=START_DATE, end=START_DATE)