refactor: Introduce utility functions for exception handling and database operations; update auth and playlist services to use new exception methods

app/services/auth.py

@@ -20,6 +20,11 @@ from app.schemas.auth import (
 )
 from app.services.oauth import OAuthUserInfo
 from app.utils.auth import JWTUtils, PasswordUtils, TokenUtils
+from app.utils.exceptions import (
+    raise_bad_request,
+    raise_not_found,
+    raise_unauthorized,
+)
 
 logger = get_logger(__name__)
 
@@ -39,10 +44,7 @@ class AuthService:
 
         # Check if email already exists
         if await self.user_repo.email_exists(request.email):
-            raise HTTPException(
+            raise_bad_request("Email address is already registered")
-                status_code=status.HTTP_400_BAD_REQUEST,
-                detail="Email address is already registered",
-            )
 
         # Hash the password
         hashed_password = PasswordUtils.hash_password(request.password)
@@ -75,27 +77,18 @@ class AuthService:
         # Get user by email
         user = await self.user_repo.get_by_email(request.email)
         if not user:
-            raise HTTPException(
+            raise_unauthorized("Invalid email or password")
-                status_code=status.HTTP_401_UNAUTHORIZED,
-                detail="Invalid email or password",
-            )
 
         # Check if user is active
         if not user.is_active:
-            raise HTTPException(
+            raise_unauthorized("Account is deactivated")
-                status_code=status.HTTP_401_UNAUTHORIZED,
-                detail="Account is deactivated",
-            )
 
         # Verify password
         if not user.password_hash or not PasswordUtils.verify_password(
             request.password,
             user.password_hash,
         ):
-            raise HTTPException(
+            raise_unauthorized("Invalid email or password")
-                status_code=status.HTTP_401_UNAUTHORIZED,
-                detail="Invalid email or password",
-            )
 
         # Generate access token
         token = self._create_access_token(user)
@@ -110,16 +103,10 @@ class AuthService:
         """Get the current authenticated user."""
         user = await self.user_repo.get_by_id(user_id)
         if not user:
-            raise HTTPException(
+            raise_not_found("User")
-                status_code=status.HTTP_404_NOT_FOUND,
-                detail="User not found",
-            )
 
         if not user.is_active:
-            raise HTTPException(
+            raise_unauthorized("Account is deactivated")
-                status_code=status.HTTP_401_UNAUTHORIZED,
-                detail="Account is deactivated",
-            )
 
         return user
 

app/services/playlist.py

@@ -10,6 +10,11 @@ from app.models.playlist import Playlist
 from app.models.sound import Sound
 from app.repositories.playlist import PlaylistRepository
 from app.repositories.sound import SoundRepository
+from app.utils.exceptions import (
+    raise_bad_request,
+    raise_internal_server_error,
+    raise_not_found,
+)
 
 logger = get_logger(__name__)
 
@@ -27,10 +32,7 @@ class PlaylistService:
         """Get a playlist by ID."""
         playlist = await self.playlist_repo.get_by_id(playlist_id)
         if not playlist:
-            raise HTTPException(
+            raise_not_found("Playlist")
-                status_code=status.HTTP_404_NOT_FOUND,
-                detail="Playlist not found",
-            )
 
         return playlist
 
@@ -47,9 +49,8 @@ class PlaylistService:
         main_playlist = await self.playlist_repo.get_main_playlist()
 
         if not main_playlist:
-            raise HTTPException(
+            raise_internal_server_error(
-                status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
+                "Main playlist not found. Make sure to run database seeding."
-                detail="Main playlist not found. Make sure to run database seeding."
             )
 
         return main_playlist

app/utils/database.py

@@ -0,0 +1,166 @@
+"""Database utility functions for common operations."""
+
+from typing import Any, Dict, List, Optional, Type, TypeVar
+from sqlmodel import select, SQLModel
+from sqlmodel.ext.asyncio.session import AsyncSession
+
+T = TypeVar("T", bound=SQLModel)
+
+
+async def create_and_save(
+    session: AsyncSession,
+    model_class: Type[T],
+    **kwargs: Any
+) -> T:
+    """Create, add, commit, and refresh a model instance.
+    
+    This consolidates the common database pattern of:
+    - instance = ModelClass(**kwargs)
+    - session.add(instance) 
+    - await session.commit()
+    - await session.refresh(instance)
+    
+    Args:
+        session: Database session
+        model_class: SQLModel class to instantiate
+        **kwargs: Arguments to pass to model constructor
+        
+    Returns:
+        Created and refreshed model instance
+    """
+    instance = model_class(**kwargs)
+    session.add(instance)
+    await session.commit()
+    await session.refresh(instance)
+    return instance
+
+
+async def get_or_create(
+    session: AsyncSession,
+    model_class: Type[T],
+    defaults: Optional[Dict[str, Any]] = None,
+    **kwargs: Any
+) -> tuple[T, bool]:
+    """Get an existing instance or create a new one.
+    
+    Args:
+        session: Database session
+        model_class: SQLModel class
+        defaults: Default values for creation (if not found)
+        **kwargs: Filter criteria for lookup
+        
+    Returns:
+        Tuple of (instance, created) where created is True if instance was created
+    """
+    # Build filter conditions
+    filters = []
+    for key, value in kwargs.items():
+        filters.append(getattr(model_class, key) == value)
+    
+    # Try to find existing instance
+    statement = select(model_class).where(*filters)
+    result = await session.exec(statement)
+    instance = result.first()
+    
+    if instance:
+        return instance, False
+    
+    # Create new instance
+    create_kwargs = {**kwargs}
+    if defaults:
+        create_kwargs.update(defaults)
+    
+    instance = await create_and_save(session, model_class, **create_kwargs)
+    return instance, True
+
+
+async def update_and_save(
+    session: AsyncSession,
+    instance: T,
+    **updates: Any
+) -> T:
+    """Update model instance fields and save to database.
+    
+    Args:
+        session: Database session
+        instance: Model instance to update
+        **updates: Field updates to apply
+        
+    Returns:
+        Updated and refreshed model instance
+    """
+    for field, value in updates.items():
+        setattr(instance, field, value)
+    
+    session.add(instance)
+    await session.commit()
+    await session.refresh(instance)
+    return instance
+
+
+async def bulk_create(
+    session: AsyncSession,
+    model_class: Type[T],
+    items: List[Dict[str, Any]]
+) -> List[T]:
+    """Create multiple model instances in bulk.
+    
+    Args:
+        session: Database session
+        model_class: SQLModel class to instantiate
+        items: List of dictionaries with model data
+        
+    Returns:
+        List of created model instances
+    """
+    instances = []
+    for item_data in items:
+        instance = model_class(**item_data)
+        session.add(instance)
+        instances.append(instance)
+    
+    await session.commit()
+    
+    # Refresh all instances
+    for instance in instances:
+        await session.refresh(instance)
+    
+    return instances
+
+
+async def delete_and_commit(
+    session: AsyncSession,
+    instance: T
+) -> None:
+    """Delete an instance and commit the transaction.
+    
+    Args:
+        session: Database session
+        instance: Model instance to delete
+    """
+    await session.delete(instance)
+    await session.commit()
+
+
+async def exists(
+    session: AsyncSession,
+    model_class: Type[T],
+    **kwargs: Any
+) -> bool:
+    """Check if a model instance exists with given criteria.
+    
+    Args:
+        session: Database session
+        model_class: SQLModel class
+        **kwargs: Filter criteria
+        
+    Returns:
+        True if instance exists, False otherwise
+    """
+    filters = []
+    for key, value in kwargs.items():
+        filters.append(getattr(model_class, key) == value)
+    
+    statement = select(model_class).where(*filters)
+    result = await session.exec(statement)
+    return result.first() is not None

app/utils/exceptions.py

@@ -0,0 +1,121 @@
+"""Utility functions for common HTTP exception patterns."""
+
+from fastapi import HTTPException, status
+
+
+def raise_not_found(resource: str, identifier: str = None) -> None:
+    """Raise a standardized 404 Not Found exception.
+    
+    Args:
+        resource: Name of the resource that wasn't found
+        identifier: Optional identifier for the specific resource
+        
+    Raises:
+        HTTPException with 404 status code
+    """
+    if identifier:
+        detail = f"{resource} with ID {identifier} not found"
+    else:
+        detail = f"{resource} not found"
+    
+    raise HTTPException(
+        status_code=status.HTTP_404_NOT_FOUND,
+        detail=detail,
+    )
+
+
+def raise_unauthorized(detail: str = "Could not validate credentials") -> None:
+    """Raise a standardized 401 Unauthorized exception.
+    
+    Args:
+        detail: Error message detail
+        
+    Raises:
+        HTTPException with 401 status code
+    """
+    raise HTTPException(
+        status_code=status.HTTP_401_UNAUTHORIZED,
+        detail=detail,
+    )
+
+
+def raise_bad_request(detail: str) -> None:
+    """Raise a standardized 400 Bad Request exception.
+    
+    Args:
+        detail: Error message detail
+        
+    Raises:
+        HTTPException with 400 status code
+    """
+    raise HTTPException(
+        status_code=status.HTTP_400_BAD_REQUEST,
+        detail=detail,
+    )
+
+
+def raise_internal_server_error(detail: str, cause: Exception = None) -> None:
+    """Raise a standardized 500 Internal Server Error exception.
+    
+    Args:
+        detail: Error message detail
+        cause: Optional underlying exception
+        
+    Raises:
+        HTTPException with 500 status code
+    """
+    if cause:
+        raise HTTPException(
+            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
+            detail=detail,
+        ) from cause
+    else:
+        raise HTTPException(
+            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
+            detail=detail,
+        )
+
+
+def raise_payment_required(detail: str = "Insufficient credits") -> None:
+    """Raise a standardized 402 Payment Required exception.
+    
+    Args:
+        detail: Error message detail
+        
+    Raises:
+        HTTPException with 402 status code
+    """
+    raise HTTPException(
+        status_code=status.HTTP_402_PAYMENT_REQUIRED,
+        detail=detail,
+    )
+
+
+def raise_forbidden(detail: str = "Access forbidden") -> None:
+    """Raise a standardized 403 Forbidden exception.
+    
+    Args:
+        detail: Error message detail
+        
+    Raises:
+        HTTPException with 403 status code
+    """
+    raise HTTPException(
+        status_code=status.HTTP_403_FORBIDDEN,
+        detail=detail,
+    )
+
+
+def raise_conflict(detail: str) -> None:
+    """Raise a standardized 409 Conflict exception.
+    
+    Args:
+        detail: Error message detail
+        
+    Raises:
+        HTTPException with 409 status code
+    """
+    raise HTTPException(
+        status_code=status.HTTP_409_CONFLICT,
+        detail=detail,
+    )

app/utils/test_helpers.py

@@ -0,0 +1,179 @@
+"""Test helper utilities for reducing code duplication."""
+
+from contextlib import asynccontextmanager
+from typing import Any, Dict, Optional, Type, TypeVar
+from unittest.mock import AsyncMock
+
+from fastapi import FastAPI
+from sqlmodel.ext.asyncio.session import AsyncSession
+from sqlmodel import SQLModel
+
+from app.models.user import User
+from app.utils.auth import JWTUtils
+
+T = TypeVar("T", bound=SQLModel)
+
+
+def create_jwt_token_data(user: User) -> Dict[str, str]:
+    """Create standardized JWT token data dictionary for a user.
+    
+    Args:
+        user: User object to create token data for
+        
+    Returns:
+        Dictionary with sub, email, and role fields
+    """
+    return {
+        "sub": str(user.id),
+        "email": user.email,
+        "role": user.role,
+    }
+
+
+def create_access_token_for_user(user: User) -> str:
+    """Create an access token for a user using standardized token data.
+    
+    Args:
+        user: User object to create token for
+        
+    Returns:
+        JWT access token string
+    """
+    token_data = create_jwt_token_data(user)
+    return JWTUtils.create_access_token(token_data)
+
+
+async def create_and_save_model(
+    session: AsyncSession, 
+    model_class: Type[T],
+    **kwargs: Any
+) -> T:
+    """Create, save, and refresh a model instance.
+    
+    This consolidates the common pattern of:
+    - model = ModelClass(**kwargs)  
+    - session.add(model)
+    - await session.commit()
+    - await session.refresh(model)
+    
+    Args:
+        session: Database session
+        model_class: SQLModel class to instantiate
+        **kwargs: Arguments to pass to model constructor
+        
+    Returns:
+        Created and refreshed model instance
+    """
+    instance = model_class(**kwargs)
+    session.add(instance)
+    await session.commit()
+    await session.refresh(instance)
+    return instance
+
+
+@asynccontextmanager
+async def override_dependencies(
+    app: FastAPI,
+    overrides: Dict[Any, Any]
+):
+    """Context manager for FastAPI dependency overrides with automatic cleanup.
+    
+    Args:
+        app: FastAPI application instance
+        overrides: Dictionary mapping dependency functions to mock implementations
+        
+    Usage:
+        async with override_dependencies(test_app, {
+            get_service: lambda: mock_service,
+            get_repo: lambda: mock_repo
+        }):
+            # Test code here
+            pass
+        # Dependencies automatically cleaned up
+    """
+    # Apply overrides
+    for dependency, override in overrides.items():
+        app.dependency_overrides[dependency] = override
+    
+    try:
+        yield
+    finally:
+        # Clean up overrides
+        for dependency in overrides:
+            app.dependency_overrides.pop(dependency, None)
+
+
+def create_mock_vlc_services() -> Dict[str, AsyncMock]:
+    """Create standard set of mocked VLC-related services.
+    
+    Returns:
+        Dictionary with mocked vlc_service, sound_repository, and credit_service
+    """
+    return {
+        "vlc_service": AsyncMock(),
+        "sound_repository": AsyncMock(),
+        "credit_service": AsyncMock(),
+    }
+
+
+def configure_mock_sound_play_success(
+    mocks: Dict[str, AsyncMock],
+    sound_data: Dict[str, Any]
+) -> None:
+    """Configure mocks for successful sound playback scenario.
+    
+    Args:
+        mocks: Dictionary of mock services from create_mock_vlc_services()
+        sound_data: Dictionary with sound properties (id, name, etc.)
+    """
+    from app.models.sound import Sound
+    
+    mock_sound = Sound(**sound_data)
+    
+    # Configure repository mock
+    mocks["sound_repository"].get_by_id.return_value = mock_sound
+    
+    # Configure credit service mocks  
+    mocks["credit_service"].validate_and_reserve_credits.return_value = None
+    mocks["credit_service"].deduct_credits.return_value = None
+    
+    # Configure VLC service mock
+    mocks["vlc_service"].play_sound.return_value = True
+
+
+def create_mock_vlc_stop_result(
+    success: bool = True,
+    processes_found: int = 3,
+    processes_killed: int = 3,
+    processes_remaining: int = 0,
+    message: Optional[str] = None,
+    error: Optional[str] = None
+) -> Dict[str, Any]:
+    """Create standardized VLC stop operation result.
+    
+    Args:
+        success: Whether operation succeeded
+        processes_found: Number of VLC processes found
+        processes_killed: Number of processes successfully killed
+        processes_remaining: Number of processes still running
+        message: Success/status message
+        error: Error message (for failed operations)
+        
+    Returns:
+        Dictionary with VLC stop operation result
+    """
+    result = {
+        "success": success,
+        "processes_found": processes_found,
+        "processes_killed": processes_killed,
+    }
+    
+    if not success:
+        result["error"] = error or "Command failed"
+        result["message"] = message or "Failed to stop VLC processes"
+    else:
+        # Always include processes_remaining for successful operations
+        result["processes_remaining"] = processes_remaining
+        result["message"] = message or f"Killed {processes_killed} VLC processes"
+    
+    return result

app/utils/validation.py

@@ -0,0 +1,140 @@
+"""Common validation utility functions."""
+
+import re
+from pathlib import Path
+from typing import Any, Optional
+
+# Password validation constants
+MIN_PASSWORD_LENGTH = 8
+
+
+def validate_email(email: str) -> bool:
+    """Validate email address format.
+
+    Args:
+        email: Email address to validate
+
+    Returns:
+        True if email format is valid, False otherwise
+    """
+    pattern = r"^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$"
+    return bool(re.match(pattern, email))
+
+
+def validate_password_strength(password: str) -> tuple[bool, str | None]:
+    """Validate password meets security requirements.
+
+    Args:
+        password: Password to validate
+
+    Returns:
+        Tuple of (is_valid, error_message)
+    """
+    if len(password) < MIN_PASSWORD_LENGTH:
+        msg = f"Password must be at least {MIN_PASSWORD_LENGTH} characters long"
+        return False, msg
+
+    if not re.search(r"[A-Z]", password):
+        return False, "Password must contain at least one uppercase letter"
+
+    if not re.search(r"[a-z]", password):
+        return False, "Password must contain at least one lowercase letter"
+
+    if not re.search(r"\d", password):
+        return False, "Password must contain at least one number"
+
+    return True, None
+
+
+def validate_filename(
+    filename: str, allowed_extensions: list[str] | None = None
+) -> bool:
+    """Validate filename format and extension.
+
+    Args:
+        filename: Filename to validate
+        allowed_extensions: List of allowed file extensions (with dots)
+
+    Returns:
+        True if filename is valid, False otherwise
+    """
+    if not filename or filename.startswith(".") or "/" in filename or "\\" in filename:
+        return False
+
+    if allowed_extensions:
+        file_path = Path(filename)
+        return file_path.suffix.lower() in [ext.lower() for ext in allowed_extensions]
+
+    return True
+
+
+def validate_audio_filename(filename: str) -> bool:
+    """Validate audio filename has allowed extension.
+
+    Args:
+        filename: Audio filename to validate
+
+    Returns:
+        True if filename has valid audio extension, False otherwise
+    """
+    audio_extensions = [".mp3", ".wav", ".flac", ".ogg", ".m4a", ".aac", ".wma"]
+    return validate_filename(filename, audio_extensions)
+
+
+def sanitize_filename(filename: str) -> str:
+    """Sanitize filename by removing/replacing invalid characters.
+
+    Args:
+        filename: Filename to sanitize
+
+    Returns:
+        Sanitized filename safe for filesystem
+    """
+    # Remove or replace problematic characters
+    sanitized = re.sub(r'[<>:"/\\|?*]', "_", filename)
+
+    # Remove leading/trailing whitespace and dots
+    sanitized = sanitized.strip(" .")
+
+    # Ensure not empty
+    if not sanitized:
+        sanitized = "untitled"
+
+    return sanitized
+
+
+def validate_url(url: str) -> bool:
+    """Validate URL format.
+
+    Args:
+        url: URL to validate
+
+    Returns:
+        True if URL format is valid, False otherwise
+    """
+    pattern = r"^https?://[^\s/$.?#].[^\s]*$"
+    return bool(re.match(pattern, url))
+
+
+def validate_positive_integer(value: Any, field_name: str = "value") -> int:
+    """Validate and convert value to positive integer.
+
+    Args:
+        value: Value to validate and convert
+        field_name: Name of field for error messages
+
+    Returns:
+        Validated positive integer
+
+    Raises:
+        ValueError: If value is not a positive integer
+    """
+    try:
+        int_value = int(value)
+        if int_value <= 0:
+            msg = f"{field_name} must be a positive integer"
+            raise ValueError(msg)
+        return int_value
+    except (TypeError, ValueError) as e:
+        msg = f"{field_name} must be a positive integer"
+        raise ValueError(msg) from e

tests/api/v1/test_player_endpoints.py

@@ -516,10 +516,9 @@ class TestPlayerEndpoints:
             "status": PlayerStatus.PLAYING.value,
             "mode": PlayerMode.CONTINUOUS.value,
             "volume": 50,
-            "current_sound_id": 1,
+            "position_ms": 5000,
-            "current_sound_index": 0,
+            "duration_ms": 30000,
-            "current_sound_position": 5000,
+            "index": 0,
-            "current_sound_duration": 30000,
             "current_sound": {
                 "id": 1,
                 "name": "Test Song",
@@ -530,11 +529,13 @@ class TestPlayerEndpoints:
                 "thumbnail": None,
                 "play_count": 0,
             },
-            "playlist_id": 1,
+            "playlist": {
-            "playlist_name": "Test Playlist",
+                "id": 1,
-            "playlist_length": 1,
+                "name": "Test Playlist",
-            "playlist_duration": 30000,
+                "length": 1,
-            "playlist_sounds": [],
+                "duration": 30000,
+                "sounds": [],
+            },
         }
         mock_player_service.get_state.return_value = mock_state
 

tests/api/v1/test_vlc_endpoints.py

@@ -1,12 +1,22 @@
 """Tests for VLC player API endpoints."""
 
-from unittest.mock import AsyncMock, patch
+from unittest.mock import AsyncMock, Mock, patch
 
 import pytest
 from httpx import AsyncClient
+from fastapi import FastAPI
 
 from app.models.sound import Sound
 from app.models.user import User
+from app.api.v1.sounds import get_vlc_player, get_sound_repository, get_credit_service
+from app.utils.test_helpers import (
+    override_dependencies,
+    create_mock_vlc_services,
+    configure_mock_sound_play_success,
+    create_mock_vlc_stop_result,
+)
+
+
 
 
 class TestVLCEndpoints:
@@ -15,68 +25,93 @@ class TestVLCEndpoints:
     @pytest.mark.asyncio
     async def test_play_sound_with_vlc_success(
         self,
+        test_app: FastAPI,
         authenticated_client: AsyncClient,
         authenticated_user: User,
     ):
         """Test successful sound playback via VLC."""
-        # Mock the VLC player service and sound repository methods
+        # Set up mocks using helper
-        with patch("app.services.vlc_player.VLCPlayerService.play_sound") as mock_play_sound:
+        mocks = create_mock_vlc_services()
-            mock_play_sound.return_value = True
         
-            with patch("app.repositories.sound.SoundRepository.get_by_id") as mock_get_by_id:
+        # Configure mocks for successful play
-                mock_sound = Sound(
+        sound_data = {
-                    id=1,
+            "id": 1,
-                    type="SDB",
+            "type": "SDB", 
-                    name="Test Sound",
+            "name": "Test Sound",
-                    filename="test.mp3",
+            "filename": "test.mp3",
-                    duration=5000,
+            "duration": 5000,
-                    size=1024,
+            "size": 1024,
-                    hash="test_hash",
+            "hash": "test_hash",
-                )
+        }
-                mock_get_by_id.return_value = mock_sound
+        configure_mock_sound_play_success(mocks, sound_data)
         
+        # Use dependency override helper
+        overrides = {
+            get_vlc_player: lambda: mocks["vlc_service"],
+            get_sound_repository: lambda: mocks["sound_repository"],
+            get_credit_service: lambda: mocks["credit_service"],
+        }
+        
+        async with override_dependencies(test_app, overrides):
             response = await authenticated_client.post("/api/v1/sounds/vlc/play/1")
             
             assert response.status_code == 200
             data = response.json()
-                assert data["success"] is True
             assert data["sound_id"] == 1
             assert data["sound_name"] == "Test Sound"
             assert "Test Sound" in data["message"]
             
             # Verify service calls
-                mock_get_by_id.assert_called_once_with(1)
+            mocks["sound_repository"].get_by_id.assert_called_once_with(1)
-                mock_play_sound.assert_called_once_with(mock_sound)
+            mocks["vlc_service"].play_sound.assert_called_once()
 
     @pytest.mark.asyncio
     async def test_play_sound_with_vlc_sound_not_found(
         self,
+        test_app: FastAPI,
         authenticated_client: AsyncClient,
         authenticated_user: User,
     ):
         """Test VLC playback when sound is not found."""
-        # Mock the sound repository to return None
+        # Set up mocks
-        with patch("app.repositories.sound.SoundRepository.get_by_id") as mock_get_by_id:
+        mock_vlc_service = AsyncMock()
-            mock_get_by_id.return_value = None
+        mock_repo = AsyncMock()
+        mock_credit_service = AsyncMock()
         
+        # Configure mocks
+        mock_repo.get_by_id.return_value = None
+        
+        # Override dependencies
+        test_app.dependency_overrides[get_vlc_player] = lambda: mock_vlc_service
+        test_app.dependency_overrides[get_sound_repository] = lambda: mock_repo
+        test_app.dependency_overrides[get_credit_service] = lambda: mock_credit_service
+        
+        try:
             response = await authenticated_client.post("/api/v1/sounds/vlc/play/999")
             
             assert response.status_code == 404
             data = response.json()
             assert "Sound with ID 999 not found" in data["detail"]
+        finally:
+            # Clean up dependency overrides (except get_db which is needed for other tests)
+            test_app.dependency_overrides.pop(get_vlc_player, None)
+            test_app.dependency_overrides.pop(get_sound_repository, None)
+            test_app.dependency_overrides.pop(get_credit_service, None)
 
     @pytest.mark.asyncio
     async def test_play_sound_with_vlc_launch_failure(
         self,
+        test_app: FastAPI,
         authenticated_client: AsyncClient,
         authenticated_user: User,
     ):
         """Test VLC playback when VLC launch fails."""
-        # Mock the VLC player service to fail
+        # Set up mocks
-        with patch("app.services.vlc_player.VLCPlayerService.play_sound") as mock_play_sound:
+        mock_vlc_service = AsyncMock()
-            mock_play_sound.return_value = False
+        mock_repo = AsyncMock()
+        mock_credit_service = AsyncMock()
         
-            with patch("app.repositories.sound.SoundRepository.get_by_id") as mock_get_by_id:
+        # Set up test data
         mock_sound = Sound(
             id=1,
             type="SDB",
@@ -86,30 +121,62 @@ class TestVLCEndpoints:
             size=1024,
             hash="test_hash",
         )
-                mock_get_by_id.return_value = mock_sound
         
+        # Configure mocks
+        mock_repo.get_by_id.return_value = mock_sound
+        mock_credit_service.validate_and_reserve_credits.return_value = None
+        mock_credit_service.deduct_credits.return_value = None
+        mock_vlc_service.play_sound.return_value = False
+        
+        # Override dependencies
+        test_app.dependency_overrides[get_vlc_player] = lambda: mock_vlc_service
+        test_app.dependency_overrides[get_sound_repository] = lambda: mock_repo
+        test_app.dependency_overrides[get_credit_service] = lambda: mock_credit_service
+        
+        try:
             response = await authenticated_client.post("/api/v1/sounds/vlc/play/1")
             
             assert response.status_code == 500
             data = response.json()
             assert "Failed to launch VLC for sound playback" in data["detail"]
+        finally:
+            # Clean up dependency overrides (except get_db which is needed for other tests)
+            test_app.dependency_overrides.pop(get_vlc_player, None)
+            test_app.dependency_overrides.pop(get_sound_repository, None)
+            test_app.dependency_overrides.pop(get_credit_service, None)
 
     @pytest.mark.asyncio
     async def test_play_sound_with_vlc_service_exception(
         self,
+        test_app: FastAPI,
         authenticated_client: AsyncClient,
         authenticated_user: User,
     ):
         """Test VLC playback when service raises an exception."""
-        # Mock the sound repository to raise an exception
+        # Set up mocks
-        with patch("app.repositories.sound.SoundRepository.get_by_id") as mock_get_by_id:
+        mock_vlc_service = AsyncMock()
-            mock_get_by_id.side_effect = Exception("Database error")
+        mock_repo = AsyncMock()
+        mock_credit_service = AsyncMock()
         
+        # Configure mocks
+        mock_repo.get_by_id.side_effect = Exception("Database error")
+        
+        # Override dependencies
+        test_app.dependency_overrides[get_vlc_player] = lambda: mock_vlc_service
+        test_app.dependency_overrides[get_sound_repository] = lambda: mock_repo
+        test_app.dependency_overrides[get_credit_service] = lambda: mock_credit_service
+        
+        try:
             response = await authenticated_client.post("/api/v1/sounds/vlc/play/1")
             
             assert response.status_code == 500
             data = response.json()
             assert "Failed to play sound" in data["detail"]
+        finally:
+            # Clean up dependency overrides (except get_db which is needed for other tests)
+            test_app.dependency_overrides.pop(get_vlc_player, None)
+            test_app.dependency_overrides.pop(get_sound_repository, None)
+            test_app.dependency_overrides.pop(get_credit_service, None)
 
     @pytest.mark.asyncio
     async def test_play_sound_with_vlc_unauthenticated(
@@ -123,21 +190,25 @@ class TestVLCEndpoints:
     @pytest.mark.asyncio
     async def test_stop_all_vlc_instances_success(
         self,
+        test_app: FastAPI,
         authenticated_client: AsyncClient,
         authenticated_user: User,
     ):
         """Test successful stopping of all VLC instances."""
-        # Mock the VLC player service
+        # Set up mock using helper
-        with patch("app.services.vlc_player.VLCPlayerService.stop_all_vlc_instances") as mock_stop_all:
+        mock_vlc_service = AsyncMock()
-            mock_result = {
+        mock_result = create_mock_vlc_stop_result(
-                "success": True,
+            success=True,
-                "processes_found": 3,
+            processes_found=3,
-                "processes_killed": 3,
+            processes_killed=3,
-                "processes_remaining": 0,
+            processes_remaining=0
-                "message": "Killed 3 VLC processes",
+        )
-            }
+        mock_vlc_service.stop_all_vlc_instances.return_value = mock_result
-            mock_stop_all.return_value = mock_result
         
+        # Use dependency override helper
+        overrides = {get_vlc_player: lambda: mock_vlc_service}
+        
+        async with override_dependencies(test_app, overrides):
             response = await authenticated_client.post("/api/v1/sounds/vlc/stop-all")
             
             assert response.status_code == 200
@@ -149,25 +220,30 @@ class TestVLCEndpoints:
             assert "Killed 3 VLC processes" in data["message"]
             
             # Verify service call
-            mock_stop_all.assert_called_once()
+            mock_vlc_service.stop_all_vlc_instances.assert_called_once()
 
     @pytest.mark.asyncio
     async def test_stop_all_vlc_instances_no_processes(
         self,
+        test_app: FastAPI,
         authenticated_client: AsyncClient,
         authenticated_user: User,
     ):
         """Test stopping VLC instances when none are running."""
-        # Mock the VLC player service
+        # Set up mock using helper
-        with patch("app.services.vlc_player.VLCPlayerService.stop_all_vlc_instances") as mock_stop_all:
+        mock_vlc_service = AsyncMock()
-            mock_result = {
+        mock_result = create_mock_vlc_stop_result(
-                "success": True,
+            success=True,
-                "processes_found": 0,
+            processes_found=0,
-                "processes_killed": 0,
+            processes_killed=0,
-                "message": "No VLC processes found",
+            message="No VLC processes found"
-            }
+        )
-            mock_stop_all.return_value = mock_result
+        mock_vlc_service.stop_all_vlc_instances.return_value = mock_result
         
+        # Use dependency override helper
+        overrides = {get_vlc_player: lambda: mock_vlc_service}
+        
+        async with override_dependencies(test_app, overrides):
             response = await authenticated_client.post("/api/v1/sounds/vlc/stop-all")
             
             assert response.status_code == 200
@@ -180,12 +256,13 @@ class TestVLCEndpoints:
     @pytest.mark.asyncio
     async def test_stop_all_vlc_instances_partial_success(
         self,
+        test_app: FastAPI,
         authenticated_client: AsyncClient,
         authenticated_user: User,
     ):
         """Test stopping VLC instances with partial success."""
-        # Mock the VLC player service
+        # Set up mock
-        with patch("app.services.vlc_player.VLCPlayerService.stop_all_vlc_instances") as mock_stop_all:
+        mock_vlc_service = AsyncMock()
         mock_result = {
             "success": True,
             "processes_found": 3,
@@ -193,8 +270,12 @@ class TestVLCEndpoints:
             "processes_remaining": 1,
             "message": "Killed 2 VLC processes",
         }
-            mock_stop_all.return_value = mock_result
+        mock_vlc_service.stop_all_vlc_instances.return_value = mock_result
         
+        # Override dependency
+        test_app.dependency_overrides[get_vlc_player] = lambda: mock_vlc_service
+        
+        try:
             response = await authenticated_client.post("/api/v1/sounds/vlc/stop-all")
             
             assert response.status_code == 200
@@ -203,16 +284,20 @@ class TestVLCEndpoints:
             assert data["processes_found"] == 3
             assert data["processes_killed"] == 2
             assert data["processes_remaining"] == 1
+        finally:
+            # Clean up dependency override
+            test_app.dependency_overrides.pop(get_vlc_player, None)
 
     @pytest.mark.asyncio
     async def test_stop_all_vlc_instances_failure(
         self,
+        test_app: FastAPI,
         authenticated_client: AsyncClient,
         authenticated_user: User,
     ):
         """Test stopping VLC instances when service fails."""
-        # Mock the VLC player service
+        # Set up mock
-        with patch("app.services.vlc_player.VLCPlayerService.stop_all_vlc_instances") as mock_stop_all:
+        mock_vlc_service = AsyncMock()
         mock_result = {
             "success": False,
             "processes_found": 0,
@@ -220,8 +305,12 @@ class TestVLCEndpoints:
             "error": "Command failed",
             "message": "Failed to stop VLC processes",
         }
-            mock_stop_all.return_value = mock_result
+        mock_vlc_service.stop_all_vlc_instances.return_value = mock_result
         
+        # Override dependency
+        test_app.dependency_overrides[get_vlc_player] = lambda: mock_vlc_service
+        
+        try:
             response = await authenticated_client.post("/api/v1/sounds/vlc/stop-all")
             
             assert response.status_code == 200
@@ -229,23 +318,34 @@ class TestVLCEndpoints:
             assert data["success"] is False
             assert data["error"] == "Command failed"
             assert data["message"] == "Failed to stop VLC processes"
+        finally:
+            # Clean up dependency override
+            test_app.dependency_overrides.pop(get_vlc_player, None)
 
     @pytest.mark.asyncio
     async def test_stop_all_vlc_instances_service_exception(
         self,
+        test_app: FastAPI,
         authenticated_client: AsyncClient,
         authenticated_user: User,
     ):
         """Test stopping VLC instances when service raises an exception."""
-        # Mock the VLC player service to raise an exception
+        # Set up mock to raise an exception
-        with patch("app.services.vlc_player.VLCPlayerService.stop_all_vlc_instances") as mock_stop_all:
+        mock_vlc_service = AsyncMock()
-            mock_stop_all.side_effect = Exception("Service error")
+        mock_vlc_service.stop_all_vlc_instances.side_effect = Exception("Service error")
         
+        # Override dependency
+        test_app.dependency_overrides[get_vlc_player] = lambda: mock_vlc_service
+        
+        try:
             response = await authenticated_client.post("/api/v1/sounds/vlc/stop-all")
             
             assert response.status_code == 500
             data = response.json()
             assert "Failed to stop VLC instances" in data["detail"]
+        finally:
+            # Clean up dependency override
+            test_app.dependency_overrides.pop(get_vlc_player, None)
 
     @pytest.mark.asyncio
     async def test_stop_all_vlc_instances_unauthenticated(
@@ -259,15 +359,17 @@ class TestVLCEndpoints:
     @pytest.mark.asyncio
     async def test_vlc_endpoints_with_admin_user(
         self,
+        test_app: FastAPI,
         authenticated_admin_client: AsyncClient,
         admin_user: User,
     ):
         """Test VLC endpoints work with admin user."""
-        # Test play endpoint with admin
+        # Set up mocks
-        with patch("app.services.vlc_player.VLCPlayerService.play_sound") as mock_play_sound:
+        mock_vlc_service = AsyncMock()
-            mock_play_sound.return_value = True
+        mock_repo = AsyncMock()
+        mock_credit_service = AsyncMock()
         
-            with patch("app.repositories.sound.SoundRepository.get_by_id") as mock_get_by_id:
+        # Set up test data
         mock_sound = Sound(
             id=1,
             type="SDB",
@@ -277,17 +379,32 @@ class TestVLCEndpoints:
             size=512,
             hash="admin_hash",
         )
-                mock_get_by_id.return_value = mock_sound
         
+        # Configure mocks
+        mock_repo.get_by_id.return_value = mock_sound
+        mock_credit_service.validate_and_reserve_credits.return_value = None
+        mock_credit_service.deduct_credits.return_value = None
+        mock_vlc_service.play_sound.return_value = True
+        
+        # Override dependencies
+        test_app.dependency_overrides[get_vlc_player] = lambda: mock_vlc_service
+        test_app.dependency_overrides[get_sound_repository] = lambda: mock_repo
+        test_app.dependency_overrides[get_credit_service] = lambda: mock_credit_service
+        
+        try:
             response = await authenticated_admin_client.post("/api/v1/sounds/vlc/play/1")
             
             assert response.status_code == 200
             data = response.json()
-                assert data["success"] is True
             assert data["sound_name"] == "Admin Test Sound"
+        finally:
+            # Clean up dependency overrides (except get_db which is needed for other tests)
+            test_app.dependency_overrides.pop(get_vlc_player, None)
+            test_app.dependency_overrides.pop(get_sound_repository, None)
+            test_app.dependency_overrides.pop(get_credit_service, None)
 
         # Test stop-all endpoint with admin
-        with patch("app.services.vlc_player.VLCPlayerService.stop_all_vlc_instances") as mock_stop_all:
+        mock_vlc_service_2 = AsyncMock()
         mock_result = {
             "success": True,
             "processes_found": 1,
@@ -295,11 +412,18 @@ class TestVLCEndpoints:
             "processes_remaining": 0,
             "message": "Killed 1 VLC processes",
         }
-            mock_stop_all.return_value = mock_result
+        mock_vlc_service_2.stop_all_vlc_instances.return_value = mock_result
         
+        # Override dependency for stop-all test
+        test_app.dependency_overrides[get_vlc_player] = lambda: mock_vlc_service_2
+        
+        try:
             response = await authenticated_admin_client.post("/api/v1/sounds/vlc/stop-all")
             
             assert response.status_code == 200
             data = response.json()
             assert data["success"] is True
             assert data["processes_killed"] == 1
+        finally:
+            # Clean up dependency override
+            test_app.dependency_overrides.pop(get_vlc_player, None)

tests/conftest.py

@@ -18,6 +18,7 @@ from app.models.plan import Plan
 from app.models.user import User
 from app.models.user_oauth import UserOauth  # Ensure model is imported for SQLAlchemy
 from app.utils.auth import JWTUtils, PasswordUtils
+from app.utils.test_helpers import create_access_token_for_user
 
 
 @pytest.fixture(scope="session")
@@ -277,28 +278,14 @@ def test_login_data() -> dict[str, str]:
 @pytest_asyncio.fixture
 async def auth_headers(test_user: User) -> dict[str, str]:
     """Create authentication headers with JWT token."""
-    token_data = {
+    access_token = create_access_token_for_user(test_user)
-        "sub": str(test_user.id),
-        "email": test_user.email,
-        "role": test_user.role,
-    }
-
-    access_token = JWTUtils.create_access_token(token_data)
-
     return {"Authorization": f"Bearer {access_token}"}
 
 
 @pytest_asyncio.fixture
 async def admin_headers(admin_user: User) -> dict[str, str]:
     """Create admin authentication headers with JWT token."""
-    token_data = {
+    access_token = create_access_token_for_user(admin_user)
-        "sub": str(admin_user.id),
-        "email": admin_user.email,
-        "role": admin_user.role,
-    }
-
-    access_token = JWTUtils.create_access_token(token_data)
-
     return {"Authorization": f"Bearer {access_token}"}
 
 
@@ -317,26 +304,12 @@ def authenticated_user(test_user: User) -> User:
 @pytest_asyncio.fixture
 async def auth_cookies(test_user: User) -> dict[str, str]:
     """Create authentication cookies with JWT token."""
-    token_data = {
+    access_token = create_access_token_for_user(test_user)
-        "sub": str(test_user.id),
-        "email": test_user.email,
-        "role": test_user.role,
-    }
-
-    access_token = JWTUtils.create_access_token(token_data)
-
     return {"access_token": access_token}
 
 
 @pytest_asyncio.fixture
 async def admin_cookies(admin_user: User) -> dict[str, str]:
     """Create admin authentication cookies with JWT token."""
-    token_data = {
+    access_token = create_access_token_for_user(admin_user)
-        "sub": str(admin_user.id),
-        "email": admin_user.email,
-        "role": admin_user.role,
-    }
-
-    access_token = JWTUtils.create_access_token(token_data)
-
     return {"access_token": access_token}

tests/repositories/test_user.py

@@ -11,6 +11,7 @@ from app.models.plan import Plan
 from app.models.user import User
 from app.repositories.user import UserRepository
 from app.utils.auth import PasswordUtils
+from app.utils.database import create_and_save
 
 
 class TestUserRepository: