Smart Contract Lottery

Purpose

Create a 100% random smart contract lottery in a python environment.

Lottery.sol

• The contract owner will choose when the lottery starts
• Users can enter the lottery with ETH based on a USD fee (10$)
• The contract owner will choose when the lottery is over
• The lottery will select a truly random winner

Development Environment

Contracts for our mocks!

Deploy_lottery.py

A python script to:

• Connect to a Blockchain (Testnet, Mainnet)
• Get an account safely
  • From a local or a forked local blockchain environment
  • A real one via the config & .env file
• Pass the price feed, vrf coordinator, link_token & keyhash addresses plus the fee to our contract
  • Real ones if we are on a real network
  • Mock ones if we are on a local blockchain environment
• Deploy our contract
• Start the lottery (Only the contract owner)
• Enter the lottery (with our account)
• End the lottery (Only the contract owner)
  • Fund the contract to get a random number
  • End the lottery
  • Sleep for a minute to make sure there was a response from fulfillRandomness
  • Show the winner

Essential_scripts.py

• Get an account safely
  • From a local or a forked local blockchain environment
  • A real one via the config & .env file
• Get contract addresses. Either mock ones or real ones
• Deploy mocks
• Fund the contract with link (To use the fulfillRandomness method)

Tests

There are 2 types of tests in this project.

- unit tests, which run on a local blockchain.

- integration tests, which run on a testnet

Unit

• Test to make sure the entrance fee is okay
• Test to make sure the lottery is open if we try to enter
• Test to make sure we can start and enter the lottery
• Test to make sure we can end the lottery
• Test to make sure the winner was chosen randomly and got all the money

Integration

• Make sure the whole program works fine

Help with the project

To run the code there are some requirements. You must install:

pipx

Install pipx by running the following on the command line: python -m pip install --user pipx then python3 -m pipx ensurepath

For more information check: Install pipx

Brownie

Install Brownie by running the following on the command line: pip install eth-brownie

For more information check: Install Brownie

This is the Lesson 7 of the freeCodeCamp.org tutorial: https://www.youtube.com/watch?v=M576WGiDBdQ with more comments.