tdd-red-green-refactor

name	tdd-red-green-refactor
description	Implement behaviour changes with Arey Pi strict Red-Green-Refactor. Use when adding features, fixing bugs, or changing production behaviour where tests must drive implementation.

TDD Red-Green-Refactor

Use this skill for production behaviour changes under Arey Pi.

TDD is mandatory unless the user explicitly chooses a non-behaviour mode or a project constraint blocks it. If blocked, report the blocker; do not claim TDD evidence.

Required Reading

Read these files when available:

• AGENTS.md
• rules/engineering/tdd.md
• rules/engineering/test-quality.md
• rules/engineering/engineering-quality.md
• rules/engineering/quality-tooling.md
• rules/core/definition-of-done.md
• rules/specs/spec-sync.md
• affected Gherkin specs under specs/features/
• existing tests and test runner configuration

Workflow

1. Understand accepted behaviour

   • Identify the canonical spec, bug report, or explicit user acceptance criteria.
   • Ask focused questions if behaviour is ambiguous.

2. Red

   • Add or update meaningful tests before production code changes.
   • Prefer tests/, test/, spec/, or equivalent dedicated test directories.
   • Do not place tests inside production source directories by default.
   • Run the narrowest relevant test command and capture failure evidence.

3. Green

   • Implement the smallest high-quality production change.
   • Avoid speculative abstractions and broad rewrites.
   • Run the failing test again and capture passing evidence.

4. Refactor

   • Improve clarity/design only while tests remain green.
   • Keep behaviour unchanged during refactor.

5. Validate

   • Run available formatter, lint/static analysis, typecheck, tests, coverage, mutation testing, or dynamic checks appropriate to risk.
   • Surface missing quality tooling as a gap.

6. Sync

   • Update specs, docs, DBML, ADRs, glossary, or architecture docs when the intended behaviour or contract changed.

Output

Return:

TDD report:
- Behaviour:
- Tests added/updated and location:
- Red evidence:
- Green evidence:
- Refactor evidence:
- Validation commands and results:
- Spec/docs/ADR/DBML/glossary impact:
- Quality notes:
- Residual risks: