fixture-driven-tdd

fixture-driven-tdd is a skill for Claude Code, Codex from recca0120/code-quest. It costs 53 tokens per session (616 once invoked), scanned A, original, MIT.

A test-driven development workflow for command-line parsers and session tests. Test-driven development means writing a failing test first, then adding the code that makes it pass, using JSON lines captured from real command-line output.

In plain words
What is it for?
Collecting CLI output as fixtures, adding new event types, building fake Claude session segments, and testing the server pipeline that processes those events.
Why use it?
It avoids tests based on guessed data and makes parser changes checkable against real CLI behavior.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/recca0120/code-quest/fixture-driven-tdd
Any agent
npx skills add recca0120/code-quest --skill fixture-driven-tdd
Clone the repo
git clone --depth 1 https://github.com/recca0120/code-quest

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for fixture-driven-tdd

README.md
[![agentmods](https://agentmods.dev/badge/skills/recca0120/code-quest/fixture-driven-tdd.svg)](https://agentmods.dev/skills/recca0120/code-quest/fixture-driven-tdd)
Your own site
<a href="https://agentmods.dev/skills/recca0120/code-quest/fixture-driven-tdd"><img src="https://agentmods.dev/badge/skills/recca0120/code-quest/fixture-driven-tdd.svg" alt="Measured on agentmods" height="20"></a>
Per session 53 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 616 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00053 $0.00616
Opus 5 $0.00026 $0.00308
Sonnet 5 $0.00011 $0.00123
Haiku 4.5 $0.00005 $0.00062

Measured 3d ago against content hash 17d640c727f4, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

fixture-driven-tdd scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 3d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.claude/skills/fixture-driven-tdd/SKILL.md · 83 lines

How it starts

The opening of the file, as written. The whole thing — 83 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Fixture-Driven TDD

Principle

Test data must come from real CLI output, never guessed. Use DB exports or capture-fixture.sh.

Fixture Locations

apps/summoner/src/__fixtures__/claude/
├── real/        # 40+ files — DB exports & real CLI recordings
└── synthetic/   # 18 files — hand-crafted for untriggerable events

Fixtures are auto-loaded by TEMPLATES in apps/summoner/src/test/fake-claude.ts.

Workflow

1. Collect fixture

# Real CLI capture
scripts/capture-fixture.sh <name> [prompt]

# Or from DB
mysql -u root -h 127.0.0.1 -P 3306 code_quest -N -e \
  "SELECT raw FROM raw_entries WHERE raw LIKE '{\"type\":\"<event_type>\"%' LIMIT 1;"

DB connection in apps/server/.envDATABASE_URL.

2. Add to fixtures

Save to apps/summoner/src/__fixtures__/claude/real/<name>.jsonl (or synthetic/ if hand-crafted).

3. Add segment builder

In apps/summoner/src/test/fake-claude.ts, add to segments object:

myEvent(param: string): string {
  const line = JSON.parse(TEMPLATES.MY_EVENT);
  line.some_field = param;
  line.uuid = `fake-my-event-${++_seq}`;
  return JSON.stringify(line);
}

4. Write test (RED)

import { segments as s } from '@code-quest/summoner/test';

// Parser test
const parsed = adapter.parseLine(s.myEvent('test'));
expect(parsed.status).toBe('ok');

// Pipeline test
const claude = createFakeSummoner().claude();
const channelId = await claude.initialize(s.init('sess'));
await claude.emit(s.myEvent('test'));
expect(claude.received('message:my_event')).toHaveLength(1);

5. Implement (GREEN) → Refactor

Anti-patterns

  • Never hand-write JSON that pretends to be CLI output
  • Never use inline JSON in tests — use segments.*() builders
  • Synthetic fixtures must be clearly marked and tracked for replacement

Reference

  • Capture script: scripts/capture-fixture.sh
  • Tracking: docs/fixture-capture-tracking.md
  • Segment builders: apps/summoner/src/test/fake-claude.ts (60+ builders)

Read the full file on GitHub · 83 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 3d ago First seen · 83 lines · 53 tokens per session scan A 17d640c727f4

Subscribe to this mod's changes

fixture-driven-tdd is a skill published in the GitHub repository recca0120/code-quest (11 stars, last pushed 2mo ago), licensed MIT. It adds 53 tokens to every session and 616 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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