Refactor test files for improved readability and consistency

- Removed unnecessary blank lines and adjusted formatting in test files.
- Ensured consistent use of commas in function calls and assertions across various test cases.
- Updated import statements for better organization and clarity.
- Enhanced mock setups in tests for better isolation and reliability.
- Improved assertions to follow a consistent style for better readability.

app/services/extraction.py

@@ -10,7 +10,6 @@ from sqlmodel.ext.asyncio.session import AsyncSession
 
 from app.core.config import settings
 from app.core.logging import get_logger
-from app.models.extraction import Extraction
 from app.models.sound import Sound
 from app.repositories.extraction import ExtractionRepository
 from app.repositories.sound import SoundRepository
@@ -155,7 +154,7 @@ class ExtractionService:
 
                 # Check if extraction already exists for this service
                 existing = await self.extraction_repo.get_by_service_and_id(
-                    service_info["service"], service_info["service_id"]
+                    service_info["service"], service_info["service_id"],
                 )
                 if existing and existing.id != extraction_id:
                     error_msg = (
@@ -180,7 +179,7 @@ class ExtractionService:
 
             # Extract audio and thumbnail
             audio_file, thumbnail_file = await self._extract_media(
-                extraction_id, extraction_url
+                extraction_id, extraction_url,
             )
 
             # Move files to final locations
@@ -238,7 +237,7 @@ class ExtractionService:
         except Exception as e:
             error_msg = str(e)
             logger.exception(
-                "Failed to process extraction %d: %s", extraction_id, error_msg
+                "Failed to process extraction %d: %s", extraction_id, error_msg,
             )
 
             # Update extraction with error
@@ -262,14 +261,14 @@ class ExtractionService:
             }
 
     async def _extract_media(
-        self, extraction_id: int, extraction_url: str
+        self, extraction_id: int, extraction_url: str,
     ) -> tuple[Path, Path | None]:
         """Extract audio and thumbnail using yt-dlp."""
         temp_dir = Path(settings.EXTRACTION_TEMP_DIR)
 
         # Create unique filename based on extraction ID
         output_template = str(
-            temp_dir / f"extraction_{extraction_id}_%(title)s.%(ext)s"
+            temp_dir / f"extraction_{extraction_id}_%(title)s.%(ext)s",
         )
 
         # Configure yt-dlp options
@@ -304,8 +303,8 @@ class ExtractionService:
             # Find the extracted files
             audio_files = list(
                 temp_dir.glob(
-                    f"extraction_{extraction_id}_*.{settings.EXTRACTION_AUDIO_FORMAT}"
-                )
+                    f"extraction_{extraction_id}_*.{settings.EXTRACTION_AUDIO_FORMAT}",
+                ),
             )
             thumbnail_files = (
                 list(temp_dir.glob(f"extraction_{extraction_id}_*.webp"))
@@ -342,7 +341,7 @@ class ExtractionService:
         """Move extracted files to their final locations."""
         # Generate clean filename based on title and service
         safe_title = self._sanitize_filename(
-            title or f"{service or 'unknown'}_{service_id or 'unknown'}"
+            title or f"{service or 'unknown'}_{service_id or 'unknown'}",
         )
 
         # Move audio file