Refactor test cases for improved readability and consistency

- Adjusted function signatures in various test files to enhance clarity by aligning parameters.
- Updated patching syntax for better readability across test cases.
- Improved formatting and spacing in test assertions and mock setups.
- Ensured consistent use of async/await patterns in async test functions.
- Enhanced comments for better understanding of test intentions.

app/core/database.py

@@ -40,8 +40,10 @@ async def get_db() -> AsyncGenerator[AsyncSession, None]:
 
 def get_session_factory() -> Callable[[], AsyncSession]:
     """Get a session factory function for services."""
+
     def session_factory() -> AsyncSession:
         return AsyncSession(engine)
+
     return session_factory