# Test-Driven Development

A disciplined approach to software development that ensures every line of production code is validated by tests written first. Introduces TDD methodology, anti-pattern detection, and orchestrated test coverage using specialized agents.

Focused on:

* **Test-first development** - Write tests before implementation, ensuring every feature is verified
* **Red-Green-Refactor cycle** - Systematic approach that builds confidence through failing tests
* **Anti-pattern detection** - Identifies common testing mistakes like mock abuse and test-only methods
* **Agent-orchestrated coverage** - Parallel test writing using specialized subagents for complex changes

## Plugin Target

* **Prevent regressions** - Every change is backed by tests that catch future breaks
* **Improve design quality** - Hard-to-test code reveals design problems early
* **Build confidence** - Watching tests fail then pass proves they actually test something
* **Accelerate development** - TDD is faster than debugging untested code in production

## Overview

The TDD plugin implements Kent Beck's Test-Driven Development methodology, proven over two decades to produce higher-quality, more maintainable software. The core principle is simple but transformative: **write the test first, watch it fail, then write minimal code to pass**.

The plugin is based on foundational works including Kent Beck's *Test-Driven Development: By Example* and the extensive research on TDD effectiveness.

## Quick Start

```bash
# Install the plugin
/plugin install tdd@NeoLabHQ/context-engineering-kit

> claude "Use TDD skill to implement email validation for user registration"

# Manually make some changes that cause test failures

# Fix failing tests
> /fix-tests
```

### After Implementation

If you implemented a new feature but have not written tests, you can use the `write-tests` command to cover it.

```bash
> claude "implement email validation for user registration"

# Write tests after you made changes
> /write-tests
```

[Usage Examples](https://cek.neolab.finance/plugins/tdd/usage-examples)

## Commands

* [/write-tests](https://cek.neolab.finance/plugins/tdd/write-tests) - Systematically add test coverage for all local code changes using specialized review and development agents
* [/fix-tests](https://cek.neolab.finance/plugins/tdd/fix-tests) - Systematically fix all failing tests after business logic changes or refactoring using orchestrated agents.

## Skills

* [test-driven-development](https://cek.neolab.finance/plugins/tdd/test-driven-development) - Test-Driven Development (TDD) skill. Comprehensive TDD methodology and anti-pattern detection guide that ensures rigorous test-first development.

## Foundation

The TDD plugin is based on decades of research and practice demonstrating significant improvements in code quality and development efficiency:

### Foundational Works

* [**Test-Driven Development: By Example**](https://www.oreilly.com/library/view/test-driven-development/0321146530/) by Kent Beck - The definitive guide to TDD methodology, introducing Red-Green-Refactor
* [**Refactoring: Improving the Design of Existing Code**](https://martinfowler.com/books/refactoring.html) by Martin Fowler - Companion work on safe code transformation under test coverage


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