Learn Solidity, Blockchain Development, & Smart Contracts (YouTube)

Lesson 7: Foundry Fund Me

This repo is from the YouTube video: Learn Solidity, Blockchain Development, & Smart Contracts: Lesson 7: Foundry Fund Me. This course, by Patrick Collins of Cyfrin, teaches Ethereum Solidity development using Foundry, a smart contract development toolchain. The GitHub repo for the course is: (https://github.com/Cyfrin/foundry-full-course-f23).

YouTube: Learn Solidity, Blockchain Devleopment, & Smart Contracts

• Foundry Fund Me
• Getting Started
  • Requirements
  • Quickstart
• Usage
  • Testing
    • Test Coverage
• Deployment to a testnet or mainnet
  • Scripts
    • Withdraw
  • Estimate gas

Getting Started

Requirements

• git
  • You'll know you did it right if you can run git --version and you see a response like git version x.x.x
• foundry
  • You'll know you did it right if you can run forge --version and you see a response like forge 0.2.0 (816e00b 2023-03-16T00:05:26.396218Z)

Quickstart

git clone https://github.com/Cyfrin/foundry-fund-me-f23
cd foundry-fund-me-f23
forge build

Usage

Deploy:

forge script scripts/DeployFundMe.s.sol

Testing

We talk about 4 test tiers in the video.

1. Unit
2. Integration
3. Forked
4. Staging

This repo we cover #1 and #3.

forge test

or

// Only run test functions matching the specified regex pattern.

forge test --match-test testFunctionName

or

forge test --fork-url $SEPOLIA_RPC_URL

Test Coverage

forge coverage

Deployment to a testnet or mainnet

1. Setup environment variables

You'll want to set your SEPOLIA_RPC_URL and PRIVATE_KEY as environment variables. You can add them to a .env file, similar to what you see in .env.example.

• PRIVATE_KEY: The private key of your account (like from metamask). NOTE: FOR DEVELOPMENT, PLEASE USE A KEY THAT DOESN'T HAVE ANY REAL FUNDS ASSOCIATED WITH IT.
  • You can learn how to export it here.
• SEPOLIA_RPC_URL: This is url of the sepolia testnet node you're working with. You can get setup with one for free from Alchemy

Optionally, add your ETHERSCAN_API_KEY if you want to verify your contract on Etherscan.

1. Get testnet ETH

Head over to faucets.chain.link and get some tesnet ETH. You should see the ETH show up in your metamask.

3. Deploy

forge script script/DeployFundMe.s.sol --rpc-url $SEPOLIA_RPC_URL --private-key $PRIVATE_KEY --broadcast --verify --etherscan-api-key $ETHERSCAN_API_KEY

Scripts

After deploy to a testnet or local net, you can run the scripts.

Using cast deployed locally example:

cast send <FUNDME_CONTRACT_ADDRESS> "fund()" --value 0.1ether --private-key <PRIVATE_KEY>

or

forge script script/FundFundMe.s.sol --rpc-url sepolia  --private-key $PRIVATE_KEY  --broadcast

Withdraw

cast send <FUNDME_CONTRACT_ADDRESS> "withdraw()"  --private-key <PRIVATE_KEY>

Estimate gas

You can estimate how much gas things cost by running:

forge snapshot

And you'll see and output file called .gas-snapshot