Add complete test infrastructure for yaml2pptx project with 245+ tests
covering unit, integration, and end-to-end scenarios.
Test structure:
- Unit tests: elements, template system, validators, loaders, utils
- Integration tests: presentation and rendering flows
- E2E tests: CLI commands (convert, check, preview)
Key features:
- PptxFileValidator for Level 2 PPTX validation (file structure,
element count, content matching, position tolerance)
- Comprehensive fixtures for test data consistency
- Mock-based testing for external dependencies
- Test images generated with PIL/Pillow
- Boundary case coverage for edge scenarios
Dependencies added:
- pytest, pytest-cov, pytest-mock
- pillow (for test image generation)
Documentation updated:
- README.md: test running instructions
- README_DEV.md: test development guide
Co-authored-by: OpenSpec change: add-comprehensive-tests
