openzeppelin-contracts/test/payment/PullPayment.test.js

const { balanceDifference } = require('../helpers/balanceDifference');
const { ether } = require('../helpers/ether');

require('../helpers/setup');

const PullPaymentMock = artifacts.require('PullPaymentMock');

contract('PullPayment', function ([_, payer, payee1, payee2]) {
  const amount = ether(17.0);

  beforeEach(async function () {
    this.contract = await PullPaymentMock.new({ value: amount });
  });

  it('can record an async payment correctly', async function () {
    await this.contract.callTransfer(payee1, 100, { from: payer });
    (await this.contract.payments(payee1)).should.be.bignumber.equal(100);
  });

  it('can add multiple balances on one account', async function () {
    await this.contract.callTransfer(payee1, 200, { from: payer });
    await this.contract.callTransfer(payee1, 300, { from: payer });
    (await this.contract.payments(payee1)).should.be.bignumber.equal(500);
  });

  it('can add balances on multiple accounts', async function () {
    await this.contract.callTransfer(payee1, 200, { from: payer });
    await this.contract.callTransfer(payee2, 300, { from: payer });

    (await this.contract.payments(payee1)).should.be.bignumber.equal(200);

    (await this.contract.payments(payee2)).should.be.bignumber.equal(300);
  });

  it('can withdraw payment', async function () {
    (await balanceDifference(payee1, async () => {
      await this.contract.callTransfer(payee1, amount, { from: payer });
      (await this.contract.payments(payee1)).should.be.bignumber.equal(amount);

      await this.contract.withdrawPayments(payee1);
    })).should.be.bignumber.equal(amount);

    (await this.contract.payments(payee1)).should.be.bignumber.equal(0);
  });
});