[Feature] Update testing setup to align with pytest conventions

[guan404ming]

Summary

Update testing setup to align with pytest conventions and improve Poetry dependency management for better development workflow consistency.

Use Case

The current testing setup has inconsistencies that make it harder for contributors to run tests reliably. By aligning with pytest conventions and Poetry best practices, we can:

• Ensure consistent test discovery and execution across different environments
• Simplify the development setup process for new contributors

Proposed Implementation

1. Move test files to conventional locations: Relocate tests from /testing/ directory to follow pytest's standard tests/ directory structure
2. Update pyproject.toml:
   • Move pytest from optional dependencies to proper dev dependencies
   • Configure pytest settings in [tool.pytest.ini_options]
3. Standardize test naming: Ensure all test files follow test_*.py convention
4. Add pytest configuration: Include proper test discovery paths, markers, and output formatting
5. Update documentation: Revise testing instructions to use standard uv run pytest commands

Alternatives Considered

• Keep current structure: Would maintain status quo but doesn't address contributor friction
• Use different testing framework: pytest is the Python standard and integrates well with Poetry
• Separate test configuration file: Using pyproject.toml is more modern and consolidated

Additional Context

• https://docs.pytest.org/en/stable/getting-started.html#group-multiple-tests-in-a-class

[rawkintrevo]

Just need to make sure poetry.lock stays out of the code base.

[rawkintrevo]

@guan404ming should this issue be closed with #566 ?

[guan404ming]

Sure, I think this one is done. Let's close this!