Smart Contract Study Project

A hands-on educational project for learning Solidity smart contract development using Truffle Suite. This repository follows a progressive learning path, starting with simple contracts and advancing toward complex patterns like DAOs and NFT marketplaces.

Overview

This project is designed for study purposes to practice and understand:

• Solidity programming fundamentals
• Smart contract patterns (access control, pausable, reentrancy guards)
• Testing smart contracts with Truffle/Mocha
• Deploying to local and test networks

See CHALLENGE.md for the complete learning roadmap with 9 progressive challenges.

Technologies Used

• Solidity 0.8.21 - Smart contract language
• Truffle Suite - Development framework
• Ganache - Local Ethereum blockchain
• Web3.js - Ethereum JavaScript API
• Mocha - Testing framework
• Infura - Ethereum node provider (for testnet deployment)

Project Structure

smart-contract/
├── contracts/           # Solidity smart contracts
├── migrations/          # Truffle deployment scripts
├── test/                # Contract test files
├── build/               # Compiled contract artifacts (generated)
├── truffle-config.js    # Truffle configuration
├── package.json         # Node.js dependencies
├── .env.example         # Environment variables template
├── CHALLENGE.md         # Learning roadmap
└── README.md            # This file

Prerequisites

• Node.js (v18 or later recommended)
• Yarn or npm
• Truffle (npm install -g truffle)

Installation

1. Clone the repository:

   git clone [email protected]:allanbatista/study-smart-contracts.git
   cd smart-contract

2. Install dependencies:

   yarn install

3. Copy the environment file and configure it:

   cp .env.example .env

   Edit .env with your credentials (required for testnet deployment only).

Usage

Local Development

1. Start a local blockchain:

   npx ganache

2. In another terminal, compile contracts:

   npx truffle compile

3. Deploy contracts to local network:

   npx truffle migrate

4. Run tests:

   npx truffle test

Testnet Deployment (Sepolia)

1. Configure .env with your credentials:

   • INFURA_PROJECT_ID: Get from Infura
   • PRIVATE_KEY: Your wallet private key (never commit this!)

2. Get test ETH from a faucet (see Testnet Resources)

3. Deploy to Sepolia:

   npx truffle migrate --network sepolia

Contracts

Contract	Description
CounterContract	Basic counter with increment functionality
CounterWithOwnerContract	Counter with owner access control and pause functionality

Testing

Run all tests:

npx truffle test

Run a specific test file:

npx truffle test test/counter_contract.js

Testnet Resources

Sepolia (Ethereum Testnet)

• Faucet: https://cloud.google.com/application/web3/faucet/ethereum/sepolia
• Explorer: https://sepolia.etherscan.io/

BNB Testnet

• Faucet: https://www.bnbchain.org/en/testnet-faucet
• Explorer: https://bscscan.com/

Learning Roadmap

This project follows a progressive learning path with 9 challenges:

1. Counter with Owner + Pausable - Access control and pause functionality
2. Whitelist / Allowlist - Permission management with mappings
3. Vault (Cofrinho) - ETH deposits/withdrawals with reentrancy guards
4. ERC-20 Token - Standard token implementation from scratch
5. Crowdfunding - Goal-based fundraising with deadlines and refunds
6. Auction - Bidding system with pull payments
7. NFT ERC-721 - Non-fungible tokens with supply caps
8. NFT Marketplace - List, buy, sell NFTs with royalties
9. DAO - Governance with proposals, voting, and timelock

See CHALLENGE.md for detailed requirements of each challenge.

Notes

My first transaction ever (on Sepolia): 0x450604f90aec9268e8f6d714b7ee88d638c22021e0c5becf2c5a62c20b7ec596