Go Kata

A collection of coding katas in Go for practicing Test-Driven Development (TDD), refactoring, and software design.

Prerequisites

• Go 1.21 or later
• A code editor (VS Code recommended with Go extension)

Installing Go

macOS

Option 1: Official Installer (Recommended)

1. Download from go.dev/dl
2. Run the .pkg installer
3. Restart your terminal

Option 2: Homebrew

brew install go

Windows

Option 1: Official Installer (Recommended)

1. Download the .msi from go.dev/dl
2. Run the installer
3. Restart your terminal/PowerShell

Option 2: Chocolatey

choco install golang

Option 3: Scoop

scoop install go

Linux

Option 1: Official Tarball (Recommended)

# Download latest (replace version as needed)
wget https://go.dev/dl/go1.22.0.linux-amd64.tar.gz

# Remove old installation and extract
sudo rm -rf /usr/local/go
sudo tar -C /usr/local -xzf go1.22.0.linux-amd64.tar.gz

# Add to PATH (add to ~/.bashrc or ~/.zshrc)
export PATH=$PATH:/usr/local/go/bin

Option 2: Package Manager

# Ubuntu/Debian (may not be latest version)
sudo apt install golang-go

# Fedora
sudo dnf install golang

Verify Installation

go version
# Should output: go version go1.2x.x ...

Installing Development Tools

golangci-lint (Linter)

⚠️ Note: The golangci-lint team recommends using binary installation or package managers over go install for consistent behavior.

macOS

brew install golangci-lint

Windows

# Chocolatey
choco install golangci-lint

# Scoop
scoop install golangci-lint

Linux / macOS / Windows (Binary Install - Recommended for CI)

# Install latest version to $(go env GOPATH)/bin
curl -sSfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sh -s -- -b $(go env GOPATH)/bin

# Or install specific version
curl -sSfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sh -s -- -b $(go env GOPATH)/bin v1.55.2

Docker (Alternative)

docker run --rm -v $(pwd):/app -w /app golangci/golangci-lint golangci-lint run

Other Go Tools

# Install mutation testing tool
go install github.com/zimmski/go-mutesting/cmd/go-mutesting@latest

# Install watch mode tool (macOS/Linux)
brew install entr  # or: apt install entr

Quick Start (First Time Setup)

# 1. Verify Go is installed
go version

# 3. Clone and enter the project
cd go-kata

# 4. Download dependencies
go mod download

# 5. Run all tests to verify setup
make test
# Or without make:
go test ./...

# 6. You're ready! Start with FizzBuzz
make fizz

Available Commands

Run make help to see all available commands:

make help         # Show all commands
make test         # Run all tests
make watch        # Watch mode (requires: brew install entr)
make coverage     # Run tests with coverage
make coverage-html # Generate HTML coverage report
make lint         # Run linter (requires: brew install golangci-lint)
make fmt          # Format code
make ci           # Run all CI checks
make install-tools # Install dev tools

Individual Kata Tests

make fizz       # FizzBuzz
make leap       # Leap Year
make stats      # Stats Calculator
make anagrams   # Anagrams
make fib        # Fibonacci
make stack      # Stack
make roman      # Roman Numerals
make prime      # Prime Factors
make tic        # Tic Tac Toe
make yahtzee    # Yahtzee
make mars       # Mars Rover
make tennis     # Tennis Refactoring
make rose       # Gilded Rose
make golf       # All Refactoring Golf
make smelly     # Smelly Tic Tac Toe
make copier     # Character Copier
make tac        # Tic Tac Toe (output)
make esa        # ESA Mars Rover
make cart       # Shopping Cart
make social     # Social Network
make smellymars # Smelly Mars Rover
make smellycart # Smelly Shopping Cart
make smellyyahtzee # Smelly Yahtzee

Refactoring Golf Holes

make golf1     # Hole 1
make golf2     # Hole 2
# ... through golf13

Watch Mode for Individual Katas

make watch-fizz  # Watch FizzBuzz
make watch-rose  # Watch Gilded Rose

Without Make

If you prefer not to use make, here are the raw Go commands:

# Run all tests
go test ./...

# Run specific kata
go test -v ./01_fizzbuzz/...

# Run with coverage
go test -cover ./...

# Format code
go fmt ./...

# Check for issues
go vet ./...

Katas

#	Kata	Description	Difficulty
01	FizzBuzz	Classic TDD starter	Beginner
02	LeapYear	Date validation logic	Beginner
03	StatsCalculator	Statistical calculations on a sequence	Beginner
04	Anagrams	Anagram generation	Beginner
05	Fibonacci	Sequence generation	Beginner
06	Stack	Data structure implementation	Beginner
07	RomanNumerals	Number conversion	Intermediate
08	PrimeFactors	Mathematical decomposition	Intermediate
09	TicTacToe	Game logic with OOP	Intermediate
10	Yahtzee	Scoring system	Intermediate
11	MarsRover	Command pattern & state	Advanced
12	Tennis	Refactoring kata	Advanced
13	GildedRose	Legacy code & testing	Advanced
14	RefactoringGolf	Progressive refactoring holes	Advanced
15	SmellyTicTacToe	Code smells identification	Advanced
16	CharacterCopier	Mocking & test doubles	Intermediate
17	TicTacToe (Output)	Game with output interface	Intermediate
18	ESA MarsRover	Multilingual rover with radio	Advanced
19	ShoppingCart	DDD & Hexagonal architecture	Advanced
20	SocialNetwork	Use case driven development	Advanced
21	Katacombs	Text adventure game	Advanced
22	SmellyMarsRover	Legacy code & test smells fixture	Advanced
23	SmellyShoppingCart	Hexagonal ports & adapters smells fixture	Advanced
25	SmellyYahtzee	Legacy code & test smells fixture (dice)	Advanced

TDD Rules

1. ✅ Write production code only to pass a failing unit test
2. ✅ Write only enough of a unit test to make it fail
3. ✅ Write only enough production code to make the failing test pass

Running Mutation Tests

# Run mutation tests (requires go-mutesting, see Installing Development Tools)
go-mutesting ./...

Project Structure

go-kata/
├── go.mod
├── go.sum
├── README.md
├── 01_fizzbuzz/
│   ├── fizzbuzz.go
│   ├── fizzbuzz_test.go
│   └── README.md
├── 02_leapyear/
│   └── ...
└── ...

Resources

• TestDesiderata by Kent Beck
• Object Calisthenics
• Transformation Priority Premise