Enforces a strict TDD cycle to ensure code quality and functionality through iterative testing.

Install

mkdir -p .claude/skills/tdd-diego-tobalina && curl -L -o skill.zip "https://agentskills.codes/api/skills/download/15614" && unzip -o skill.zip -d .claude/skills/tdd-diego-tobalina && rm skill.zip

Installs to .claude/skills/tdd-diego-tobalina

Activation

This is the description your AI agent reads to decide when to run this skill — the better it matches your request, the more reliably it fires.

Test-Driven Development workflow. Write failing test first, then implement minimum code to pass.
96 charsno explicit “when” trigger
Intermediate

Key capabilities

  • Write a single failing test for expected behavior
  • Implement the minimum code to make the test pass
  • Repeat the cycle for subsequent requirements
  • Ask for requirements if they are not clear
  • Show the written test to the user before proceeding

How it works

This skill guides development through the Test-Driven Development (TDD) workflow, starting with a failing test, then implementing minimal code to pass it, and finally refactoring.

Inputs & outputs

You give it
A new feature requirement or bug to fix
You get back
Implemented code with corresponding passing tests, following the RED-GREEN-REFACTOR cycle

When to use tdd

  • Implement feature using tdd
  • Write failing unit tests
  • Refactor existing code
  • Follow tdd process

About this skill

TDD Workflow

Implement using strict Test-Driven Development.

Process

1. RED - Write Failing Test First

  • Write ONE test that describes expected behavior
  • Run test - confirm it FAILS for the right reason
  • Show test to user before proceeding

2. GREEN - Minimum Code to Pass

  • Write the MINIMUM code to make test pass
  • No extra features, no optimization
  • Run test - confirm it PASSES

3. REFACTOR - Improve Code

  • Clean up code while keeping tests green
  • Apply patterns and best practices
  • Run tests after each change

4. REPEAT

  • Move to next requirement
  • Write next failing test
  • Continue cycle

My Role

When asked to implement a feature:

  1. Ask for requirements if not clear
  2. Write the test first - show it to user
  3. Run the test - confirm it fails
  4. Implement minimum code to pass
  5. Refactor if needed
  6. Repeat for next requirement

Rules

  • NEVER write production code without a failing test
  • ONE test at a time
  • Tests must fail before implementation
  • Keep cycles short (< 10 minutes each)

Test Naming

methodName_scenario_expectedResult

Examples:

  • create_withValidData_returnsUser
  • findById_notFound_throwsException

Test Quality Checks

  • Test name follows: method_scenario_expected
  • Test has Given-When-Then structure
  • One concept per test
  • No logic in tests
  • Tests are independent

Commands

# Java/Maven
mvn test -Dtest=ClassName#methodName

# Node.js/Vitest
npx vitest run --reporter=verbose

# Run specific test
npx vitest run path/to/test.ts

Never Do

  • Write production code before tests
  • Write multiple tests before implementing
  • Skip the refactor phase
  • Leave tests incomplete

Start by asking: "What behavior should we test first?"

When not to use it

  • When writing production code without a failing test first
  • When writing multiple tests before implementing code
  • When skipping the refactor phase of development

Limitations

  • Only one test should be written at a time
  • Tests must fail before implementation of production code
  • Cycles of RED-GREEN-REFACTOR should be kept short

How it compares

This workflow strictly enforces writing tests before any production code, ensuring that every piece of functionality is covered by a test, unlike traditional development where tests might be written after implementation.

Compared to similar skills

tdd side by side with the closest alternatives in the catalog.

SkillInstallsUpdatedSafetyDifficulty
tdd (this skill)06moReviewIntermediate
python-testing-patterns772moReviewIntermediate
dependency-upgrade265moReviewIntermediate
test-cases577moNo flagsBeginner

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