openzeppelin-contracts/test/token/ERC20/ERC20Pausable.test.js

const { accounts, contract } = require('@openzeppelin/test-environment');

const { BN, expectRevert } = require('@openzeppelin/test-helpers');

const { expect } = require('chai');

const ERC20PausableMock = contract.fromArtifact('ERC20PausableMock');

describe('ERC20Pausable', function () {
  const [ holder, recipient, anotherAccount ] = accounts;

  const initialSupply = new BN(100);

  const name = 'My Token';
  const symbol = 'MTKN';

  beforeEach(async function () {
    this.token = await ERC20PausableMock.new(name, symbol, holder, initialSupply);
  });

  describe('pausable token', function () {
    describe('transfer', function () {
      it('allows to transfer when unpaused', async function () {
        await this.token.transfer(recipient, initialSupply, { from: holder });

        expect(await this.token.balanceOf(holder)).to.be.bignumber.equal('0');
        expect(await this.token.balanceOf(recipient)).to.be.bignumber.equal(initialSupply);
      });

      it('allows to transfer when paused and then unpaused', async function () {
        await this.token.pause();
        await this.token.unpause();

        await this.token.transfer(recipient, initialSupply, { from: holder });

        expect(await this.token.balanceOf(holder)).to.be.bignumber.equal('0');
        expect(await this.token.balanceOf(recipient)).to.be.bignumber.equal(initialSupply);
      });

      it('reverts when trying to transfer when paused', async function () {
        await this.token.pause();

        await expectRevert(this.token.transfer(recipient, initialSupply, { from: holder }),
          'ERC20Pausable: token transfer while paused'
        );
      });
    });

    describe('transfer from', function () {
      const allowance = new BN(40);

      beforeEach(async function () {
        await this.token.approve(anotherAccount, allowance, { from: holder });
      });

      it('allows to transfer from when unpaused', async function () {
        await this.token.transferFrom(holder, recipient, allowance, { from: anotherAccount });

        expect(await this.token.balanceOf(recipient)).to.be.bignumber.equal(allowance);
        expect(await this.token.balanceOf(holder)).to.be.bignumber.equal(initialSupply.sub(allowance));
      });

      it('allows to transfer when paused and then unpaused', async function () {
        await this.token.pause();
        await this.token.unpause();

        await this.token.transferFrom(holder, recipient, allowance, { from: anotherAccount });

        expect(await this.token.balanceOf(recipient)).to.be.bignumber.equal(allowance);
        expect(await this.token.balanceOf(holder)).to.be.bignumber.equal(initialSupply.sub(allowance));
      });

      it('reverts when trying to transfer from when paused', async function () {
        await this.token.pause();

        await expectRevert(this.token.transferFrom(
          holder, recipient, allowance, { from: anotherAccount }), 'ERC20Pausable: token transfer while paused'
        );
      });
    });
  });
});