Add comprehensive tests for scheduled task repository, scheduler service, and task handlers

- Implemented tests for ScheduledTaskRepository covering task creation, retrieval, filtering, and status updates.
- Developed tests for SchedulerService including task creation, cancellation, user task retrieval, and maintenance jobs.
- Created tests for TaskHandlerRegistry to validate task execution for various types, including credit recharge and sound playback.
- Ensured proper error handling and edge cases in task execution scenarios.
- Added fixtures and mocks to facilitate isolated testing of services and repositories.

app/main.py

@@ -11,14 +11,27 @@ from app.core.database import get_session_factory, init_db
 from app.core.logging import get_logger, setup_logging
 from app.middleware.logging import LoggingMiddleware
 from app.services.extraction_processor import extraction_processor
-from app.services.player import initialize_player_service, shutdown_player_service
+from app.services.player import initialize_player_service, shutdown_player_service, get_player_service
 from app.services.scheduler import SchedulerService
 from app.services.socket import socket_manager
 
 
+scheduler_service = None
+
+
+def get_global_scheduler_service() -> SchedulerService:
+    """Get the global scheduler service instance."""
+    global scheduler_service
+    if scheduler_service is None:
+        raise RuntimeError("Scheduler service not initialized")
+    return scheduler_service
+
+
 @asynccontextmanager
 async def lifespan(_app: FastAPI) -> AsyncGenerator[None]:
     """Application lifespan context manager for setup and teardown."""
+    global scheduler_service
+    
     setup_logging()
     logger = get_logger(__name__)
     logger.info("Starting application")
@@ -35,17 +48,23 @@ async def lifespan(_app: FastAPI) -> AsyncGenerator[None]:
     logger.info("Player service started")
 
     # Start the scheduler service
-    scheduler_service = SchedulerService(get_session_factory())
-    await scheduler_service.start()
-    logger.info("Scheduler service started")
+    try:
+        player_service = get_player_service()  # Get the initialized player service
+        scheduler_service = SchedulerService(get_session_factory(), player_service)
+        await scheduler_service.start()
+        logger.info("Enhanced scheduler service started")
+    except Exception:
+        logger.exception("Failed to start scheduler service - continuing without it")
+        scheduler_service = None
 
     yield
 
     logger.info("Shutting down application")
 
     # Stop the scheduler service
-    await scheduler_service.stop()
-    logger.info("Scheduler service stopped")
+    if scheduler_service:
+        await scheduler_service.stop()
+        logger.info("Scheduler service stopped")
 
     # Stop the player service
     await shutdown_player_service()