openzeppelin-contracts/test/governance/utils/Votes.behavior.js

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

const { MAX_UINT256, ZERO_ADDRESS } = constants;

const { fromRpcSig } = require('ethereumjs-util');
const ethSigUtil = require('eth-sig-util');
const Wallet = require('ethereumjs-wallet').default;

const { shouldBehaveLikeEIP6372 } = require('./EIP6372.behavior');

const { getDomain, domainType, domainSeparator } = require('../../helpers/eip712');
const { clockFromReceipt } = require('../../helpers/time');

const Delegation = [
  { name: 'delegatee', type: 'address' },
  { name: 'nonce', type: 'uint256' },
  { name: 'expiry', type: 'uint256' },
];

function shouldBehaveLikeVotes(mode = 'blocknumber') {
  shouldBehaveLikeEIP6372(mode);

  describe('run votes workflow', function () {
    it('initial nonce is 0', async function () {
      expect(await this.votes.nonces(this.account1)).to.be.bignumber.equal('0');
    });

    it('domain separator', async function () {
      expect(await this.votes.DOMAIN_SEPARATOR()).to.equal(domainSeparator(await getDomain(this.votes)));
    });

    describe('delegation with signature', function () {
      const delegator = Wallet.generate();
      const delegatorAddress = web3.utils.toChecksumAddress(delegator.getAddressString());
      const nonce = 0;

      const buildAndSignData = async (contract, message, pk) => {
        const data = await getDomain(contract).then(domain => ({
          primaryType: 'Delegation',
          types: { EIP712Domain: domainType(domain), Delegation },
          domain,
          message,
        }));
        return fromRpcSig(ethSigUtil.signTypedMessage(pk, { data }));
      };

      beforeEach(async function () {
        await this.votes.$_mint(delegatorAddress, this.NFT0);
      });

      it('accept signed delegation', async function () {
        const { v, r, s } = await buildAndSignData(
          this.votes,
          {
            delegatee: delegatorAddress,
            nonce,
            expiry: MAX_UINT256,
          },
          delegator.getPrivateKey(),
        );

        expect(await this.votes.delegates(delegatorAddress)).to.be.equal(ZERO_ADDRESS);

        const { receipt } = await this.votes.delegateBySig(delegatorAddress, nonce, MAX_UINT256, v, r, s);
        const timepoint = await clockFromReceipt[mode](receipt);

        expectEvent(receipt, 'DelegateChanged', {
          delegator: delegatorAddress,
          fromDelegate: ZERO_ADDRESS,
          toDelegate: delegatorAddress,
        });
        expectEvent(receipt, 'DelegateVotesChanged', {
          delegate: delegatorAddress,
          previousBalance: '0',
          newBalance: '1',
        });

        expect(await this.votes.delegates(delegatorAddress)).to.be.equal(delegatorAddress);

        expect(await this.votes.getVotes(delegatorAddress)).to.be.bignumber.equal('1');
        expect(await this.votes.getPastVotes(delegatorAddress, timepoint - 1)).to.be.bignumber.equal('0');
        await time.advanceBlock();
        expect(await this.votes.getPastVotes(delegatorAddress, timepoint)).to.be.bignumber.equal('1');
      });

      it('rejects reused signature', async function () {
        const { v, r, s } = await buildAndSignData(
          this.votes,
          {
            delegatee: delegatorAddress,
            nonce,
            expiry: MAX_UINT256,
          },
          delegator.getPrivateKey(),
        );

        await this.votes.delegateBySig(delegatorAddress, nonce, MAX_UINT256, v, r, s);

        await expectRevert(
          this.votes.delegateBySig(delegatorAddress, nonce, MAX_UINT256, v, r, s),
          'Votes: invalid nonce',
        );
      });

      it('rejects bad delegatee', async function () {
        const { v, r, s } = await buildAndSignData(
          this.votes,
          {
            delegatee: delegatorAddress,
            nonce,
            expiry: MAX_UINT256,
          },
          delegator.getPrivateKey(),
        );

        const receipt = await this.votes.delegateBySig(this.account1Delegatee, nonce, MAX_UINT256, v, r, s);
        const { args } = receipt.logs.find(({ event }) => event === 'DelegateChanged');
        expect(args.delegator).to.not.be.equal(delegatorAddress);
        expect(args.fromDelegate).to.be.equal(ZERO_ADDRESS);
        expect(args.toDelegate).to.be.equal(this.account1Delegatee);
      });

      it('rejects bad nonce', async function () {
        const { v, r, s } = await buildAndSignData(
          this.votes,
          {
            delegatee: delegatorAddress,
            nonce,
            expiry: MAX_UINT256,
          },
          delegator.getPrivateKey(),
        );

        await expectRevert(
          this.votes.delegateBySig(delegatorAddress, nonce + 1, MAX_UINT256, v, r, s),
          'Votes: invalid nonce',
        );
      });

      it('rejects expired permit', async function () {
        const expiry = (await time.latest()) - time.duration.weeks(1);

        const { v, r, s } = await buildAndSignData(
          this.votes,
          {
            delegatee: delegatorAddress,
            nonce,
            expiry,
          },
          delegator.getPrivateKey(),
        );

        await expectRevert(
          this.votes.delegateBySig(delegatorAddress, nonce, expiry, v, r, s),
          'Votes: signature expired',
        );
      });
    });

    describe('set delegation', function () {
      describe('call', function () {
        it('delegation with tokens', async function () {
          await this.votes.$_mint(this.account1, this.NFT0);
          expect(await this.votes.delegates(this.account1)).to.be.equal(ZERO_ADDRESS);

          const { receipt } = await this.votes.delegate(this.account1, { from: this.account1 });
          const timepoint = await clockFromReceipt[mode](receipt);

          expectEvent(receipt, 'DelegateChanged', {
            delegator: this.account1,
            fromDelegate: ZERO_ADDRESS,
            toDelegate: this.account1,
          });
          expectEvent(receipt, 'DelegateVotesChanged', {
            delegate: this.account1,
            previousBalance: '0',
            newBalance: '1',
          });

          expect(await this.votes.delegates(this.account1)).to.be.equal(this.account1);

          expect(await this.votes.getVotes(this.account1)).to.be.bignumber.equal('1');
          expect(await this.votes.getPastVotes(this.account1, timepoint - 1)).to.be.bignumber.equal('0');
          await time.advanceBlock();
          expect(await this.votes.getPastVotes(this.account1, timepoint)).to.be.bignumber.equal('1');
        });

        it('delegation without tokens', async function () {
          expect(await this.votes.delegates(this.account1)).to.be.equal(ZERO_ADDRESS);

          const { receipt } = await this.votes.delegate(this.account1, { from: this.account1 });
          expectEvent(receipt, 'DelegateChanged', {
            delegator: this.account1,
            fromDelegate: ZERO_ADDRESS,
            toDelegate: this.account1,
          });
          expectEvent.notEmitted(receipt, 'DelegateVotesChanged');

          expect(await this.votes.delegates(this.account1)).to.be.equal(this.account1);
        });
      });
    });

    describe('change delegation', function () {
      beforeEach(async function () {
        await this.votes.$_mint(this.account1, this.NFT0);
        await this.votes.delegate(this.account1, { from: this.account1 });
      });

      it('call', async function () {
        expect(await this.votes.delegates(this.account1)).to.be.equal(this.account1);

        const { receipt } = await this.votes.delegate(this.account1Delegatee, { from: this.account1 });
        const timepoint = await clockFromReceipt[mode](receipt);

        expectEvent(receipt, 'DelegateChanged', {
          delegator: this.account1,
          fromDelegate: this.account1,
          toDelegate: this.account1Delegatee,
        });
        expectEvent(receipt, 'DelegateVotesChanged', {
          delegate: this.account1,
          previousBalance: '1',
          newBalance: '0',
        });
        expectEvent(receipt, 'DelegateVotesChanged', {
          delegate: this.account1Delegatee,
          previousBalance: '0',
          newBalance: '1',
        });

        expect(await this.votes.delegates(this.account1)).to.be.equal(this.account1Delegatee);

        expect(await this.votes.getVotes(this.account1)).to.be.bignumber.equal('0');
        expect(await this.votes.getVotes(this.account1Delegatee)).to.be.bignumber.equal('1');
        expect(await this.votes.getPastVotes(this.account1, timepoint - 1)).to.be.bignumber.equal('1');
        expect(await this.votes.getPastVotes(this.account1Delegatee, timepoint - 1)).to.be.bignumber.equal('0');
        await time.advanceBlock();
        expect(await this.votes.getPastVotes(this.account1, timepoint)).to.be.bignumber.equal('0');
        expect(await this.votes.getPastVotes(this.account1Delegatee, timepoint)).to.be.bignumber.equal('1');
      });
    });

    describe('getPastTotalSupply', function () {
      beforeEach(async function () {
        await this.votes.delegate(this.account1, { from: this.account1 });
      });

      it('reverts if block number >= current block', async function () {
        await expectRevert(this.votes.getPastTotalSupply(5e10), 'future lookup');
      });

      it('returns 0 if there are no checkpoints', async function () {
        expect(await this.votes.getPastTotalSupply(0)).to.be.bignumber.equal('0');
      });

      it('returns the latest block if >= last checkpoint block', async function () {
        const { receipt } = await this.votes.$_mint(this.account1, this.NFT0);
        const timepoint = await clockFromReceipt[mode](receipt);
        await time.advanceBlock();
        await time.advanceBlock();

        expect(await this.votes.getPastTotalSupply(timepoint - 1)).to.be.bignumber.equal('0');
        expect(await this.votes.getPastTotalSupply(timepoint + 1)).to.be.bignumber.equal('1');
      });

      it('returns zero if < first checkpoint block', async function () {
        await time.advanceBlock();
        const { receipt } = await this.votes.$_mint(this.account1, this.NFT1);
        const timepoint = await clockFromReceipt[mode](receipt);
        await time.advanceBlock();
        await time.advanceBlock();

        expect(await this.votes.getPastTotalSupply(timepoint - 1)).to.be.bignumber.equal('0');
        expect(await this.votes.getPastTotalSupply(timepoint + 1)).to.be.bignumber.equal('1');
      });

      it('generally returns the voting balance at the appropriate checkpoint', async function () {
        const t1 = await this.votes.$_mint(this.account1, this.NFT1);
        await time.advanceBlock();
        await time.advanceBlock();
        const t2 = await this.votes.$_burn(this.NFT1);
        await time.advanceBlock();
        await time.advanceBlock();
        const t3 = await this.votes.$_mint(this.account1, this.NFT2);
        await time.advanceBlock();
        await time.advanceBlock();
        const t4 = await this.votes.$_burn(this.NFT2);
        await time.advanceBlock();
        await time.advanceBlock();
        const t5 = await this.votes.$_mint(this.account1, this.NFT3);
        await time.advanceBlock();
        await time.advanceBlock();

        t1.timepoint = await clockFromReceipt[mode](t1.receipt);
        t2.timepoint = await clockFromReceipt[mode](t2.receipt);
        t3.timepoint = await clockFromReceipt[mode](t3.receipt);
        t4.timepoint = await clockFromReceipt[mode](t4.receipt);
        t5.timepoint = await clockFromReceipt[mode](t5.receipt);

        expect(await this.votes.getPastTotalSupply(t1.timepoint - 1)).to.be.bignumber.equal('0');
        expect(await this.votes.getPastTotalSupply(t1.timepoint)).to.be.bignumber.equal('1');
        expect(await this.votes.getPastTotalSupply(t1.timepoint + 1)).to.be.bignumber.equal('1');
        expect(await this.votes.getPastTotalSupply(t2.timepoint)).to.be.bignumber.equal('0');
        expect(await this.votes.getPastTotalSupply(t2.timepoint + 1)).to.be.bignumber.equal('0');
        expect(await this.votes.getPastTotalSupply(t3.timepoint)).to.be.bignumber.equal('1');
        expect(await this.votes.getPastTotalSupply(t3.timepoint + 1)).to.be.bignumber.equal('1');
        expect(await this.votes.getPastTotalSupply(t4.timepoint)).to.be.bignumber.equal('0');
        expect(await this.votes.getPastTotalSupply(t4.timepoint + 1)).to.be.bignumber.equal('0');
        expect(await this.votes.getPastTotalSupply(t5.timepoint)).to.be.bignumber.equal('1');
        expect(await this.votes.getPastTotalSupply(t5.timepoint + 1)).to.be.bignumber.equal('1');
      });
    });

    // The following tests are a adaptation of
    // https://github.com/compound-finance/compound-protocol/blob/master/tests/Governance/CompTest.js.
    describe('Compound test suite', function () {
      beforeEach(async function () {
        await this.votes.$_mint(this.account1, this.NFT0);
        await this.votes.$_mint(this.account1, this.NFT1);
        await this.votes.$_mint(this.account1, this.NFT2);
        await this.votes.$_mint(this.account1, this.NFT3);
      });

      describe('getPastVotes', function () {
        it('reverts if block number >= current block', async function () {
          await expectRevert(this.votes.getPastVotes(this.account2, 5e10), 'future lookup');
        });

        it('returns 0 if there are no checkpoints', async function () {
          expect(await this.votes.getPastVotes(this.account2, 0)).to.be.bignumber.equal('0');
        });

        it('returns the latest block if >= last checkpoint block', async function () {
          const { receipt } = await this.votes.delegate(this.account2, { from: this.account1 });
          const timepoint = await clockFromReceipt[mode](receipt);
          await time.advanceBlock();
          await time.advanceBlock();

          const latest = await this.votes.getVotes(this.account2);
          expect(await this.votes.getPastVotes(this.account2, timepoint)).to.be.bignumber.equal(latest);
          expect(await this.votes.getPastVotes(this.account2, timepoint + 1)).to.be.bignumber.equal(latest);
        });

        it('returns zero if < first checkpoint block', async function () {
          await time.advanceBlock();
          const { receipt } = await this.votes.delegate(this.account2, { from: this.account1 });
          const timepoint = await clockFromReceipt[mode](receipt);
          await time.advanceBlock();
          await time.advanceBlock();

          expect(await this.votes.getPastVotes(this.account2, timepoint - 1)).to.be.bignumber.equal('0');
        });
      });
    });
  });
}

module.exports = {
  shouldBehaveLikeVotes,
};