hardhat-template/test/Lock.ts

import { time, loadFixture } from '@nomicfoundation/hardhat-toolbox/network-helpers';
import { anyValue } from '@nomicfoundation/hardhat-chai-matchers/withArgs';
import { expect } from 'chai';
import hre from 'hardhat';

describe('Lock', function () {
    // We define a fixture to reuse the same setup in every test.
    // We use loadFixture to run this setup once, snapshot that state,
    // and reset Hardhat Network to that snapshot in every test.
    async function deployOneYearLockFixture() {
        const ONE_YEAR_IN_SECS = 365 * 24 * 60 * 60;
        const ONE_GWEI = 1_000_000_000;

        const lockedAmount = ONE_GWEI;
        const unlockTime = (await time.latest()) + ONE_YEAR_IN_SECS;

        // Contracts are deployed using the first signer/account by default
        const [owner, otherAccount] = await hre.ethers.getSigners();

        const Lock = await hre.ethers.getContractFactory('Lock');
        const lock = await Lock.deploy(unlockTime, { value: lockedAmount });

        return { lock, unlockTime, lockedAmount, owner, otherAccount };
    }

    describe('Deployment', function () {
        it('Should set the right unlockTime', async function () {
            const { lock, unlockTime } = await loadFixture(deployOneYearLockFixture);

            expect(await lock.unlockTime()).to.equal(unlockTime);
        });

        it('Should set the right owner', async function () {
            const { lock, owner } = await loadFixture(deployOneYearLockFixture);

            expect(await lock.owner()).to.equal(owner.address);
        });

        it('Should receive and store the funds to lock', async function () {
            const { lock, lockedAmount } = await loadFixture(deployOneYearLockFixture);

            expect(await hre.ethers.provider.getBalance(lock.target)).to.equal(lockedAmount);
        });

        it('Should fail if the unlockTime is not in the future', async function () {
            // We don't use the fixture here because we want a different deployment
            const latestTime = await time.latest();
            const Lock = await hre.ethers.getContractFactory('Lock');
            await expect(Lock.deploy(latestTime, { value: 1 })).to.be.revertedWith(
                'Unlock time should be in the future',
            );
        });
    });

    describe('Withdrawals', function () {
        describe('Validations', function () {
            it('Should revert with the right error if called too soon', async function () {
                const { lock } = await loadFixture(deployOneYearLockFixture);

                await expect(lock.withdraw()).to.be.revertedWith("You can't withdraw yet");
            });

            it('Should revert with the right error if called from another account', async function () {
                const { lock, unlockTime, otherAccount } = await loadFixture(deployOneYearLockFixture);

                // We can increase the time in Hardhat Network
                await time.increaseTo(unlockTime);

                // We use lock.connect() to send a transaction from another account
                await expect(lock.connect(otherAccount).withdraw()).to.be.revertedWith("You aren't the owner");
            });

            it("Shouldn't fail if the unlockTime has arrived and the owner calls it", async function () {
                const { lock, unlockTime } = await loadFixture(deployOneYearLockFixture);

                // Transactions are sent using the first signer by default
                await time.increaseTo(unlockTime);

                await expect(lock.withdraw()).not.to.be.reverted;
            });
        });

        describe('Events', function () {
            it('Should emit an event on withdrawals', async function () {
                const { lock, unlockTime, lockedAmount } = await loadFixture(deployOneYearLockFixture);

                await time.increaseTo(unlockTime);

                await expect(lock.withdraw()).to.emit(lock, 'Withdrawal').withArgs(lockedAmount, anyValue); // We accept any value as `when` arg
            });
        });

        describe('Transfers', function () {
            it('Should transfer the funds to the owner', async function () {
                const { lock, unlockTime, lockedAmount, owner } = await loadFixture(deployOneYearLockFixture);

                await time.increaseTo(unlockTime);

                await expect(lock.withdraw()).to.changeEtherBalances([owner, lock], [lockedAmount, -lockedAmount]);
            });
        });
    });
});