rails-tdd-slices
Installation
SKILL.md
Rails TDD Slices
Use this skill when the hardest part of the task is deciding where TDD should start.
Core principle: Start at the highest-value boundary that proves the behavior with the least unnecessary setup.
Quick Reference
| Change type | First spec | Path | Why |
|---|---|---|---|
| API contract, params, status code, JSON shape | Request spec | spec/requests/ |
Proves the real HTTP contract |
| Domain rule on a cohesive record or value object | Model spec | spec/models/ |
Fast feedback on domain behavior |
| Multi-step orchestration across collaborators | Service spec | spec/services/ |
Focuses on the workflow boundary |
| Enqueue/run/retry/discard behavior | Job spec | spec/jobs/ |
Captures async semantics directly |
| Critical Turbo/Stimulus or browser-visible flow | System spec | spec/system/ |
Use only when browser interaction is the real risk |
| Engine routing, generators, host integration | Engine spec | spec/requests/ or engine path |
Normal app specs miss engine wiring — see rails-engine-testing |
| Bug fix | Reproduction spec | Where the bug is observed | Proves the fix and prevents regression |
| Unsure between layers | Higher boundary first | — | Easier to prove real behavior before drilling down |