fix(docs): add missing testing docs

[paul-nechifor]

No description provided.

[greptile-apps]

Greptile Summary

This PR adds a new comprehensive testing documentation file (docs/development/testing.md) that was missing from the development docs, and updates the test duration estimate in the main README from 3 minutes to 1 minute.

The new testing guide covers:

• Test type taxonomy (unit, integration, functional, e2e) and the pragmatic fast/slow test categorization
• Usage instructions for ./bin/pytest-fast and ./bin/pytest-slow scripts
• Best practices for writing tests, including fixture and mocking patterns
• Useful pytest command-line options reference

The documentation is well-structured and provides practical guidance that aligns with the project's existing pytest configuration in pyproject.toml.

Confidence Score: 5/5

• This PR is safe to merge with no risk - documentation-only changes
• This is a documentation-only PR that adds missing testing documentation and updates a time estimate. No code changes that could introduce bugs or break functionality. The new testing.md file provides accurate information that aligns with the existing project structure (verified pytest scripts exist and pyproject.toml configuration matches descriptions).
• No files require special attention

Important Files Changed

Filename	Overview
docs/development/README.md	Updated test duration estimate from 3 minutes to 1 minute in setup instructions
docs/development/testing.md	New comprehensive testing documentation covering test types, fast/slow test patterns, pytest usage, fixtures, mocking, and pytest options

_{Last reviewed commit: 989bb84}

[greptile-apps]

_{2 files reviewed, no comments}

_{Edit Code Review Agent Settings | Greptile}