🎰 Foundry Smart Contract Lottery - SGDlab67

Course Completion: This repository marks the successful completion of Lesson 9: Smart Contract Lottery from the Cyfrin Foundry Solidity Course, concluding the Foundry Fundamentals section.

📝 Updates from Original Course

1. V2.5 of Chainlink VRF uses a uint256 as a subId instead of a uint64 - this repo reflects that change with appropriate mocks for version 2.5.
2. Uses 0.1.0 of the foundry-devops package which doesn't require ffi=true

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• About
• Getting Started
  • Requirements
  • Quickstart
• Usage
  • Start a local node
  • Library
  • Deploy
  • Deploy - Other Network
  • Testing
    • Test Coverage
• Deployment to a testnet or mainnet
  • Scripts
  • Estimate gas
• Formatting
• Additional Info
• Acknowledgments

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About

A provably fair, decentralized lottery smart contract built with Foundry. This project implements:

• Chainlink VRF V2.5 for verifiable random number generation
• Chainlink Automation for trustless upkeep execution
• Comprehensive unit and fork testing
• Deployment scripts for local and testnet environments

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Getting Started

Requirements

• git
  • Verify: git --version → git version x.x.x
• foundry
  • Verify: forge --version → forge 0.2.0 (...)

Quickstart

git clone https://github.com/SGDlab67/foundry-smart-contract-lottery-sgd
cd foundry-smart-contract-lottery-sgd
forge build

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Usage

Start a local node

make anvil

Library

If you encounter issues installing the Chainlink library:

forge install smartcontractkit/chainlink-brownie-contracts@0.6.1 --no-commit

Deploy

Deploy to local node (must be running in another terminal):

make deploy

Deploy - Other Network

See Deployment to a testnet or mainnet

Testing

This repo covers the following test tiers:

Tier	Type	Covered
1	Unit	✅
2	Integration	❌
3	Forked	✅
4	Staging	❌

# Run all tests
forge test

# Run with fork
forge test --fork-url $SEPOLIA_RPC_URL

Test Coverage

forge coverage

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Deployment to a testnet or mainnet

1. Setup environment variables

Create a .env file (see .env.example):

• PRIVATE_KEY: Your wallet private key (use a dev wallet with no real funds)
• SEPOLIA_RPC_URL: Sepolia testnet RPC URL (free from Alchemy)
• ETHERSCAN_API_KEY: (Optional) For contract verification

2. Get testnet ETH

Visit faucets.chain.link to get Sepolia ETH.

3. Deploy

make deploy ARGS="--network sepolia"

This automatically:

• Creates a Chainlink VRF Subscription
• Adds your contract as a consumer

4. Register Chainlink Automation Upkeep

1. Go to automation.chain.link
2. Register new upkeep with Custom logic trigger
3. Documentation

Scripts

# Enter raffle
cast send <RAFFLE_CONTRACT_ADDRESS> "enterRaffle()" --value 0.1ether --private-key <PRIVATE_KEY> --rpc-url $SEPOLIA_RPC_URL

# Create VRF Subscription
make createSubscription ARGS="--network sepolia"

Estimate gas

forge snapshot

Output: .gas-snapshot

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Formatting

forge fmt

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Additional Info

About chainlink-brownie-contracts

The chainlink-brownie-contracts repository is official - owned and maintained by the Chainlink team (smartcontractkit org).

Why use it?

• Official releases come through npm
• This repo packages npm releases for Foundry compatibility
• Avoids using unreleased code from the main chainlink repo

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Acknowledgments

This project was built following the Cyfrin Updraft Foundry Fundamentals course by Patrick Collins.

Course Progress: ✅ Foundry Fundamentals Complete!

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Author

SGDlab67

Built with 🔨 Foundry | Powered by ⛓️ Chainlink

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