test-driven-development

test-driven-development is a skill for Claude Code from gylove1994/superpowers-deepseek-v4. It costs 17 tokens per session (2,469 once invoked), scanned A, a copy of compose:tdd, MIT.

A test-first development guide, where TDD means writing a test, watching it fail, then writing the smallest code that makes it pass.

In plain words
What is it for?
Use it for new features, bug fixes, refactoring, and behavior changes. It defines the Red-Green-Refactor cycle and exceptions that require human approval.
Why use it?
It prevents implementation code from being written before there is a failing test that proves what behavior is missing.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the superpowers-deepseek-v4 plugin — 19 skills, 1 hook shipped together

Good fit Use it for new features, bug fixes, refactoring, and behavior changes. It defines the Red-Green-Refactor cycle and exceptions that require human approval.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/gylove1994/superpowers-deepseek-v4/test-driven-development
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.

Any agent
npx skills add gylove1994/superpowers-deepseek-v4 --skill test-driven-development
Clone the repo
git clone --depth 1 https://github.com/gylove1994/superpowers-deepseek-v4

Made for: Claude Code.

Or install superpowers-deepseek-v4, the plugin that ships this one along with the rest of its 19 skills, 1 hook.

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 test-driven-development

README.md
[![agentmods](https://agentmods.dev/badge/skills/gylove1994/superpowers-deepseek-v4/test-driven-development.svg)](https://agentmods.dev/skills/gylove1994/superpowers-deepseek-v4/test-driven-development)
Your own site
<a href="https://agentmods.dev/skills/gylove1994/superpowers-deepseek-v4/test-driven-development"><img src="https://agentmods.dev/badge/skills/gylove1994/superpowers-deepseek-v4/test-driven-development.svg" alt="Measured on agentmods" height="20"></a>
Per session 17 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,469 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin 89% copy Near-identical to another mod 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 5.1 $0.00017 $0.02469
Opus 5 $0.00009 $0.01234
Sonnet 5 $0.00003 $0.00494
Haiku 4.5 $0.00002 $0.00247

Measured 8d ago against content hash 079caaa5a71b, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

test-driven-development 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 8d 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.

Origin

This is a copy

89% identical to compose:tdd — 40 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

skills/test-driven-development/SKILL.md · 378 lines

How it starts

The opening of the file, as written. The whole thing — 378 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Test-Driven Development (TDD)

Overview

Write the test first. Watch it fail. Write minimal code to pass.

Core principle: If you didn't watch the test fail, you don't know if it tests the right thing.

Violating the letter of the rules is violating the spirit of the rules.

When to Use

Always:

  • New features
  • Bug fixes
  • Refactoring
  • Behavior changes

Exceptions (ask your human partner):

  • Throwaway prototypes
  • Generated code
  • Configuration files

Thinking "skip TDD just this once"? Stop. That's rationalization.

Do not write tests, production code, or any other file until the worktree gate completes (or a Step 0 skip applies).

The Iron Law

NO PRODUCTION CODE WITHOUT A FAILING TEST FIRST

Write code before the test? Delete it. Start over.

No exceptions:

  • Don't keep it as "reference"
  • Don't "adapt" it while writing tests
  • Don't look at it
  • Delete means delete

Implement fresh from tests. Period.

Red-Green-Refactor

digraph tdd_cycle {
    rankdir=LR;
    red [label="RED\nWrite failing test", shape=box, style=filled, fillcolor="#ffcccc"];
    verify_red [label="Verify fails\ncorrectly", shape=diamond];
    green [label="GREEN\nMinimal code", shape=box, style=filled, fillcolor="#ccffcc"];
    verify_green [label="Verify passes\nAll green", shape=diamond];
    refactor [label="REFACTOR\nClean up", shape=box, style=filled, fillcolor="#ccccff"];
    next [label="Next", shape=ellipse];

    red -> verify_red;
    verify_red -> green [label="yes"];
    verify_red -> red [label="wrong\nfailure"];
    green -> verify_green;
    verify_green -> refactor [label="yes"];
    verify_green -> green [label="no"];
    refactor -> verify_green [label="stay\ngreen"];
    verify_green -> next;
    next -> red;
}

RED - Write Failing Test

Write one minimal test showing what should happen.

Read the full file on GitHub · 378 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 8d ago First seen · 378 lines · 17 tokens per session scan A 079caaa5a71b

Subscribe to this mod's changes

test-driven-development is a skill published in the GitHub repository gylove1994/superpowers-deepseek-v4 (10 stars, last pushed 1mo ago), licensed MIT. It adds 17 tokens to every session and 2,469 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. It is 89% identical to compose:tdd, differing in 40 lines, and is treated as a copy.