perf: optimize pytest speed with collection and parallel execution improvements

[JacobCoffee]

Summary

Implemented pytest performance optimizations based on best practices from awesome-pytest-speedup.

Performance Improvements

Collection Speed (25% faster)

• Before: 1.58s
• After: 1.18s
• Improvement: 25% faster

Test Execution (with parallel)

• Before (sequential): ~23s
• After (parallel): ~10s
• Improvement: 58% faster

Total Time (collection + execution with parallel)

• Before: ~25s
• After: ~11s
• Overall improvement: 56% faster

Changes

1. Collection Optimizations

• ✅ Added `norecursedirs` to skip `.git`, `node_modules`, `docs`, `.venv`, etc.
• ✅ Disabled unnecessary builtin pytest plugins (`doctest`, `pastebin`, `legacypath`)
• ✅ Set `PYTHONDONTWRITEBYTECODE=1` in `Makefile` and CI workflows

2. Network Access Prevention

• ✅ Added `pytest-socket` to prevent inadvertent network calls
• ✅ Configured `--disable-socket --allow-unix-socket`
• ✅ Added `@pytest.mark.enable_socket` marker for tests that need network

3. Parallel Execution (opt-in)

• ✅ Added `pytest-xdist` for parallel test execution
• ✅ Made parallel execution opt-in via `pytest -n auto`
• ✅ Sequential execution remains default for safety

Files Changed

• `.env.example` - Added `PYTHONDONTWRITEBYTECODE=1`
• `.github/workflows/ci.yml` - Added env vars for all jobs
• `Makefile` - Added `PYTHONDONTWRITEBYTECODE = 1`
• `pyproject.toml` - Updated pytest config and dependencies
• `tests/README.md` - Added performance documentation and chart
• `uv.lock` - Updated dependencies

Usage

Default (Sequential, Safe)

```bash
make test
```

Parallel (Faster, Opt-in)

```bash
pytest -n auto
```

Quick Feedback

```bash

Run only failed tests

pytest --lf

Run failed first, then rest

pytest --ff
```

Test Results

• ✅ Same 23 pre-existing failures as main branch
• ✅ No new test failures introduced
• ✅ All prek hooks passed
• ✅ CI should pass with same results

Documentation

See detailed performance comparison and usage guide in `tests/README.md`.

Acknowledgments

Optimizations based on awesome-pytest-speedup by @zupo.

🤖 Generated with Claude Code

Summary by Sourcery

Improve pytest performance and reliability by optimizing test collection, tightening network access during tests, and enabling optional parallel execution.

New Features:

• Introduce optional parallel test execution via pytest-xdist to speed up large test suites.
• Add network access control in tests using pytest-socket with an opt-in marker for tests that legitimately require network access.

Enhancements:

• Optimize pytest collection by excluding unnecessary directories and disabling unneeded built-in plugins.
• Standardize PYTHONDONTWRITEBYTECODE across local, CI, and environment configuration to reduce filesystem overhead during tests.

Build:

• Set PYTHONDONTWRITEBYTECODE in the Makefile to avoid writing .pyc files during local test runs.

CI:

• Configure CI workflows to run with PYTHONDONTWRITEBYTECODE enabled for faster, cleaner test execution.

Documentation:

• Expand tests/README.md with detailed pytest performance metrics, optimization techniques, and guidance for running tests sequentially or in parallel.

Tests:

• Update pytest configuration to support faster collection, controlled network access, and optional parallel execution for the test suite.

Chores:

• Refresh dependency lockfile to capture new test-related dependencies and configuration changes.