Remove redundant self._next_triggers construction and add AndTrigger test.

docs/versionhistory.rst

@@ -30,6 +30,7 @@ APScheduler, see the :doc:`migration section <migration>`.
   (PR by MohammadAmin Vahedinia)
 - Fixed the shutdown procedure of the Redis event broker
 - Fixed ``SQLAlchemyDataStore`` not respecting custom schema name when creating enums
+- Fixed skipped intervals with overlapping schedules in ``AndTrigger``. (#911 <https://github.com/agronholm/apscheduler/issues/911>_; PR by Bennett Meares)
 
 **4.0.0a4**
 

src/apscheduler/triggers/combining.py

@@ -87,7 +87,6 @@ def next(self) -> datetime | None:
 
             # If all the fire times were within the threshold, return the earliest one
             if latest_fire_time - earliest_fire_time <= self.threshold:
-                self._next_fire_times = [t.next() for t in self.triggers]
                 return earliest_fire_time
         else:
             raise MaxIterationsReached

tests/triggers/test_combining.py

@@ -1,11 +1,13 @@
 from __future__ import annotations
 
-from datetime import datetime, timedelta
+from datetime import datetime, timedelta, timezone
 
 import pytest
 
 from apscheduler import MaxIterationsReached
+from apscheduler.triggers.calendarinterval import CalendarIntervalTrigger
 from apscheduler.triggers.combining import AndTrigger, OrTrigger
+from apscheduler.triggers.cron import CronTrigger
 from apscheduler.triggers.date import DateTrigger
 from apscheduler.triggers.interval import IntervalTrigger
 
@@ -62,6 +64,126 @@ def test_repr(self, timezone, serializer):
             "threshold=1.0, max_iterations=10000)"
         )
 
+    @pytest.mark.parametrize(
+        "left_kwargs,right_kwargs,start_time,expected_datetimes",
+        [
+            (
+                {"_class": "IntervalTrigger", "hours": 6},
+                {"_class": "IntervalTrigger", "hours": 12},
+                datetime(2024, 5, 1, 0, 0, 0, tzinfo=timezone.utc),
+                [
+                    datetime(2024, 5, 1, 0, 0, 0, tzinfo=timezone.utc),
+                    datetime(2024, 5, 1, 12, 0, 0, tzinfo=timezone.utc),
+                    datetime(2024, 5, 2, 0, 0, 0, tzinfo=timezone.utc),
+                ],
+            ),
+            (
+                {"_class": "IntervalTrigger", "days": 1},
+                {"_class": "IntervalTrigger", "weeks": 1},
+                datetime(2024, 5, 1, 0, 0, 0, tzinfo=timezone.utc),
+                [
+                    datetime(2024, 5, 1, 0, 0, 0, tzinfo=timezone.utc),
+                    datetime(2024, 5, 8, 0, 0, 0, tzinfo=timezone.utc),
+                    datetime(2024, 5, 15, 0, 0, 0, tzinfo=timezone.utc),
+                ],
+            ),
+            (
+                {
+                    "_class": "CronTrigger",
+                    "day_of_week": "mon-fri",
+                    "hour": "*",
+                    "timezone": timezone.utc,
+                },
+                {"_class": "IntervalTrigger", "hours": 12},
+                datetime(2024, 5, 3, 0, 0, 0, tzinfo=timezone.utc),
+                [
+                    datetime(2024, 5, 3, 0, 0, 0, tzinfo=timezone.utc),
+                    datetime(2024, 5, 3, 12, 0, 0, tzinfo=timezone.utc),
+                    datetime(2024, 5, 6, 0, 0, 0, tzinfo=timezone.utc),
+                ],
+            ),
+            (
+                {
+                    "_class": "CronTrigger",
+                    "day_of_week": "mon-fri",
+                    "timezone": timezone.utc,
+                },
+                {"_class": "IntervalTrigger", "days": 4},
+                datetime(2024, 5, 13, 0, 0, 0, tzinfo=timezone.utc),
+                [
+                    datetime(2024, 5, 13, 0, 0, 0, tzinfo=timezone.utc),
+                    datetime(2024, 5, 17, 0, 0, 0, tzinfo=timezone.utc),
+                    datetime(2024, 5, 21, 0, 0, 0, tzinfo=timezone.utc),
+                    datetime(2024, 5, 29, 0, 0, 0, tzinfo=timezone.utc),
+                ],
+            ),
+            (
+                {
+                    "_class": "CalendarIntervalTrigger",
+                    "months": 1,
+                    "timezone": timezone.utc,
+                },
+                {
+                    "_class": "CronTrigger",
+                    "day_of_week": "mon-fri",
+                    "timezone": timezone.utc,
+                },
+                datetime(2024, 1, 1, 0, 0, 0, tzinfo=timezone.utc),
+                [
+                    datetime(2024, 1, 1, 0, 0, 0, tzinfo=timezone.utc),
+                    datetime(2024, 2, 1, 0, 0, 0, tzinfo=timezone.utc),
+                    datetime(2024, 3, 1, 0, 0, 0, tzinfo=timezone.utc),
+                    datetime(2024, 4, 1, 0, 0, 0, tzinfo=timezone.utc),
+                    datetime(2024, 5, 1, 0, 0, 0, tzinfo=timezone.utc),
+                    datetime(2024, 7, 1, 0, 0, 0, tzinfo=timezone.utc),
+                    datetime(2024, 8, 1, 0, 0, 0, tzinfo=timezone.utc),
+                    datetime(2024, 10, 1, 0, 0, 0, tzinfo=timezone.utc),
+                    datetime(2024, 11, 1, 0, 0, 0, tzinfo=timezone.utc),
+                ],
+            ),
+        ],
+    )
+    def test_overlapping_triggers(
+        self, left_kwargs, right_kwargs, start_time, expected_datetimes
+    ):
+        """
+        Verify that the `AndTrigger` fires at the intersection of two triggers.
+        """
+        trigger_classes = {
+            "CronTrigger": CronTrigger,
+            "IntervalTrigger": IntervalTrigger,
+            "CalendarIntervalTrigger": CalendarIntervalTrigger,
+        }
+        left_trigger_class = trigger_classes[left_kwargs.pop("_class")]
+        right_trigger_class = trigger_classes[right_kwargs.pop("_class")]
+
+        left_kwargs.update(
+            {
+                (
+                    "start_time"
+                    if left_trigger_class is not CalendarIntervalTrigger
+                    else "start_date"
+                ): start_time,
+            }
+        )
+        right_kwargs.update(
+            {
+                (
+                    "start_time"
+                    if right_trigger_class is not CalendarIntervalTrigger
+                    else "start_date"
+                ): start_time,
+            }
+        )
+
+        left_trigger = left_trigger_class(**left_kwargs)
+        right_trigger = right_trigger_class(**right_kwargs)
+        and_trigger = AndTrigger([left_trigger, right_trigger])
+
+        for expected_datetime in expected_datetimes:
+            next_datetime = and_trigger.next()
+            assert next_datetime == expected_datetime
+
 
 class TestOrTrigger:
     def test_two_datetriggers(self, timezone, serializer):