Lesson 4 - Tests and Scripts

Writing unit tests for Ballot.sol

• More on Ether.js functions and utilities
• Bytes32 and Strings conversion
• Helper functions inside test scripts
• Unit tests structure and nested tests

Code reference for tests

import { expect } from "chai";
import { ethers } from "hardhat";
// eslint-disable-next-line node/no-missing-import
import { Ballot } from "../../typechain";

const PROPOSALS = ["Proposal 1", "Proposal 2", "Proposal 3"];

function convertStringArrayToBytes32(array: string[]) {
  const bytes32Array = [];
  for (let index = 0; index < array.length; index++) {
    bytes32Array.push(ethers.utils.formatBytes32String(array[index]));
  }
  return bytes32Array;
}

describe("Ballot", function () {
  let ballotContract: Ballot;

  this.beforeEach(async function () {
    const ballotFactory = await ethers.getContractFactory("Ballot");
    ballotContract = await ballotFactory.deploy(
      convertStringArrayToBytes32(PROPOSALS)
    );
    await ballotContract.deployed();
  });

  describe("when the contract is deployed", function () {
    it("has the provided proposals", async function () {
      for (let index = 0; index < PROPOSALS.length; index++) {
        const proposal = await ballotContract.proposals(index);
        expect(ethers.utils.parseBytes32String(proposal.name)).to.eq(
          PROPOSALS[index]
        );
      }
    });

    it("has zero votes for all proposals", async function () {});
    it("sets the deployer address as chairperson", async function () {});
    it("sets the voting weight for the chairperson as 1", async function () {});
  });

  describe("when the chairperson interacts with the giveRightToVote function in the contract", function () {
    it("gives right to vote for another address", async function () {});
    it("can not give right to vote for someone that has voted", async function () {});
    it("can not give right to vote for someone that has already voting rights", async function () {});
  });

  describe("when the voter interact with the vote function in the contract", function () {});

  describe("when the voter interact with the delegate function in the contract", function () {});

  describe("when the an attacker interact with the giveRightToVote function in the contract", function () {});

  describe("when the an attacker interact with the vote function in the contract", function () {});

  describe("when the an attacker interact with the delegate function in the contract", function () {});

  describe("when someone interact with the winningProposal function before any votes are cast", function () {});

  describe("when someone interact with the winningProposal function after one vote is cast for the first proposal", function () {});

  describe("when someone interact with the winnerName function before any votes are cast", function () {});

  describe("when someone interact with the winnerName function after one vote is cast for the first proposal", function () {});

  describe("when someone interact with the winningProposal function and winnerName after 5 random votes are cast for the proposals", function () {});
});

Using scripts to automate operations

• Running a script with yarn and node, ts-node and/or hardhat
• Ballot deployment script
• Passing arguments
• Passing variables to the deployment script
• Environment files
• Providers
• Connecting to a testnet with a RPC Provider
• Running scripts on chain
• Script for giving voting rights to a given address
• Dealing with transactions in scripts

References

https://www.typescripttutorial.net/typescript-tutorial/typescript-hello-world/

https://nodejs.org/docs/latest/api/process.html#processargv

https://docs.ethers.io/v5/api/providers/

https://docs.ethers.io/v5/api/contract/contract-factory/

import { ethers } from "hardhat";

const PROPOSALS = ["Proposal 1", "Proposal 2", "Proposal 3"];

async function main() {
  console.log("Deploying Ballot contract");
  console.log("Proposals: ");
  PROPOSALS.forEach((element, index) => {
    console.log(`Proposal N. ${index + 1}: ${element}`);
  });
  // TODO
}

main().catch((error) => {
  console.error(error);
  process.exitCode = 1;
});

Running scripts

yarn run hardhat .\scripts\Ballot\deployment.ts

Running scripts with arguments

yarn run ts-node --files .\scripts\Ballot\deployment.ts "arg1" "arg2" "arg3

Homework

• Read the references
• Finish covering other operations with scripts

Weekend Project

• Form groups of 3 to 5 students
• Structure scripts to
  • Deploy
  • Query proposals
  • Give vote right passing an address as input
  • Cast a vote to a ballot passing contract address and proposal as input and using the wallet in environment
  • Delegate my vote passing user address as input and using the wallet in environment
  • Query voting result and print to console
• Publish the project in Github
• Run the scripts with a set of proposals, cast and delegate votes and inspect results
• Write a report detailing the addresses, transaction hashes, description of the operation script being executed and console output from script execution for each step (Deployment, giving voting rights, casting/delegating and querying results).
• (Extra) Use TDD methodology