feat: implement async scheduler with lifespan management and update README

tests/test_scheduler.py

@@ -0,0 +1,62 @@
+import pytest
+from apscheduler import ConflictPolicy
+from apscheduler.triggers.interval import IntervalTrigger
+
+import app.services.scheduler as scheduler_service
+
+
+@pytest.mark.anyio
+async def test_scheduler_lifespan_starts_and_stops_scheduler(monkeypatch) -> None:
+    events = []
+    data_store = object()
+    event_broker = object()
+
+    class SchedulerStub:
+        async def __aenter__(self):
+            events.append("enter")
+            return self
+
+        async def __aexit__(self, *_args: object) -> None:
+            events.append("exit")
+
+        async def add_schedule(
+            self, func, trigger, *, id: str, conflict_policy: ConflictPolicy
+        ) -> None:
+            events.append(("schedule", func, trigger, id, conflict_policy))
+
+        async def start_in_background(self) -> None:
+            events.append("start")
+
+    scheduler = SchedulerStub()
+
+    def create_data_store(actual_engine, *, schema):
+        assert actual_engine is scheduler_service.engine
+        assert schema == "scheduler"
+        return data_store
+
+    def create_event_broker(*, client_or_url):
+        assert client_or_url == (
+            scheduler_service.global_settings.redis_url.unicode_string()
+        )
+        return event_broker
+
+    def create_scheduler(actual_data_store, actual_event_broker):
+        assert actual_data_store is data_store
+        assert actual_event_broker is event_broker
+        return scheduler
+
+    monkeypatch.setattr(scheduler_service, "SQLAlchemyDataStore", create_data_store)
+    monkeypatch.setattr(scheduler_service, "RedisEventBroker", create_event_broker)
+    monkeypatch.setattr(scheduler_service, "AsyncScheduler", create_scheduler)
+
+    async with scheduler_service.scheduler_lifespan():
+        assert events[0] == "enter"
+        event_type, func, trigger, schedule_id, conflict_policy = events[1]
+        assert event_type == "schedule"
+        assert func is scheduler_service.tick
+        assert isinstance(trigger, IntervalTrigger)
+        assert schedule_id == "tick-sql-25"
+        assert conflict_policy is ConflictPolicy.replace
+        assert events[2:] == ["start"]
+
+    assert events[-1] == "exit"