Refactoring Legacy Code and Implementing TDD for New Code/Features

This repository is a collection of Test-Driven Development (TDD) Katas and Legacy Refactoring Katas, designed to write clean, maintainable, and testable code.

Objectives

• Refactor Legacy Code: Improve the structure and quality of existing codebases without changing their external behavior.

• Promote TDD Practices: Encourage the habit of writing tests before implementing functionality.

  1. Use FIRST Principles
  2. Use Red-Green-Refactor
  3. Boundary Testing
  4. Fake It (Till You Make It)
  5. Learning Tests
  6. One to many
  7. Triangulation
  8. Backout
  9. Test Doubles

Contents

1. Legacy Refactoring Kata

This excercise focusses on improving poorly written code while preserving functionality. Examples include:

• Expense Report Generator Kata

2. TDD Katas

These exercises are aimed at practicing TDD principles by building solutions incrementally with tests. Examples include:

• FizzBuzz Kata
• RockPaperScissors Kata
• AgeCalculator Kata
• EvenDigit Kata
• String Calculator Kata

How to Use

1. Clone the Repository:

   git clone https://github.com/Zafeer/tdd-refactor-legacy.git
   cd tdd-refactor-legacy

2. Set Up the Environment: Install the necessary dependencies for Typescript (i.e. NodeJS if not already installed). Preconfigured with linting and formatting

   npm i

3. Pick an Exercise: Navigate to the desired kata directory and follow the README for specific instructions.

4. Write Tests: Start by writing approval tests(if legacy), failing tests, implement functionality, and refactor iteratively.

5. Run Tests: Use vitest to verify your solution:

   npm run test:watch  # JavaScript/TypeScript

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