Expanded test coverage for file path name generation functionality:
- Added test for normal file ID and extension
- Added test for boundary values (ID=0, empty extension)
- Added test for large file ID values with common extensions
- Added test for special character handling in extensions
- Added test for string type file ID conversion
- Added test for timestamp format verification in generated path
- Added test for path name uniqueness validation
- Improved test case documentation and structure
🤖 Generated with [Claude Code](https://claude.ai/code)
Co-Authored-By: Claude <noreply@anthropic.com>
