Test-driven development — red-green-refactor, AAA pattern and test doubles
Strict TDD methodology: red-green-refactor cycle, AAA test structure, FIRST principles, test doubles (dummies, stubs, fakes, spies, mocks) and anti-pattern guidance
- What
- Strict TDD methodology: red-green-refactor cycle, AAA test structure, FIRST principles, test doubles (dummies, stubs, fakes, spies, mocks) and anti-pattern guidance
- Cost
- Free
- Needs
- a codebase to build or change — the skill is a testing methodology the agent enforces, not software
- Install
- Copy the installer prompt below into your Muse — your agent does the rest.
Curated by Skill Harbor — @bobmatnyc's TDD skill: a rigorous test-driven development methodology, not just "write tests". Enforces the red-green-refactor cycle — write the failing test first, make the minimal change to pass, refactor mercilessly — with the AAA pattern (Arrange, Act, Assert), FIRST principles (Fast, Independent, Repeatable, Self-validating, Timely), a full taxonomy of test doubles (dummies, stubs, fakes, spies, mocks and when each applies), test-naming conventions, coverage philosophy, and anti-patterns to avoid. Honest caveats: two older TDD fiches already exist in the catalog (obra-tdd and addyosmani-test-driven-development) — this one is kept for its strict methodology and test-doubles depth; check whether the existing ones fit before installing a third. MIT licensed (manifest record authoritative; the skill file's own Apache-2.0 mention is superseded by the manifest). Skill Harbor never reviews the code, review it yourself before use. Discovered via skills.sh.
Version:
Install
Prerequisites: a codebase to build or change — the skill is a testing methodology the agent enforces, not software Install "Test-driven development — red-green-refactor, AAA pattern and test doubles" for me. It gives my agent @bobmatnyc's strict TDD methodology: the red-green-refactor cycle (failing test first, minimal change, merciless refactor), AAA test structure, FIRST principles, the full test-doubles taxonomy (dummies, stubs, fakes, spies, mocks) with usage rules, test-naming conventions, coverage philosophy and anti-patterns. NOTE: two older TDD listings already exist in the catalog (obra-tdd, addyosmani-test-driven-development) — confirm this one's strict methodology fits your need before installing a third. MIT-licensed (manifest record authoritative). Repository: https://github.com/bobmatnyc/claude-mpm-skills/blob/main/universal/testing/test-driven-development/SKILL.md 1. Fetch the SKILL.md file (and any helper files) from the repository path into a temporary folder and summarize what it does in one or two sentences. 2. Safety check: review the SKILL.md and scripts for anything suspicious (unexpected network calls, shell commands, credential harvesting). This repo should contain zero secrets in code. Verify that holds here; STOP on any red flag and tell me. 3. Install it as a skill: copy SKILL.md and its helper files into the agent's skills directory, in a folder named "test-driven-development". 4. Verify with no network calls: frontmatter valid, files in place. 5. Report what was installed, where, and what I still need to do myself (e.g. point the agent at the feature to build TDD-style and state your test framework; nothing else — it's a methodology). GitHub is optional: if I have a GitHub account or the gh CLI, you may use it; otherwise public access is fine. Never require it unless it's in the prerequisites above. Rules: don't touch anything outside the temp folder and the install target. If anything looks off, stop and ask me.
Questions
How do I install a build?
Every product page includes a copy-paste install prompt. Paste it into your Muse and it sets the build up for you — no manual configuration.
Where does my money go?
Straight to the seller. Skill Harbor never processes payments: checkout happens on the seller’s own page, usually Stripe.
What does the ✓ next to a creator’s name mean?
It means we confirmed the identity of the person behind the listing. It says nothing about the code itself — always check a build before installing it.