Add a VestingWallet

contracts/finance/vesting/ERC20VestingVoting.sol

@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.0;
+
+import "../../token/ERC20/extensions/ERC20Votes.sol";
+import "./ERC20VestingWallet.sol";
+
+/**
+ * @title ERC20VestingWalletVotes
+ * @dev This is an extension to {ERC20VestingWallet} that allow the voting with tokens that are locked. The beneficiary can
+ * delegate the voting power associated with vesting tokens to another wallet.
+ */
+contract ERC20VestingWalletVoting is ERC20VestingWallet {
+    constructor(
+        address beneficiaryAddress,
+        uint256 startTimestamp,
+        uint256 durationSeconds
+    ) ERC20VestingWallet(beneficiaryAddress, startTimestamp, durationSeconds) {}
+
+    /**
+     * @dev Delegate the voting right of tokens currently vesting
+     */
+    function delegate(address token, address delegatee) public virtual onlyBeneficiary() {
+        ERC20Votes(token).delegate(delegatee);
+    }
+}

contracts/finance/ERC20VestingWallet.sol → contracts/finance/vesting/ERC20VestingWallet.sol

@@ -1,22 +1,18 @@
 // SPDX-License-Identifier: MIT
 pragma solidity ^0.8.0;
 
-import "../token/ERC20/extensions/ERC20Votes.sol";
-import "../token/ERC20/utils/SafeERC20.sol";
-import "../utils/Context.sol";
+import "../../token/ERC20/utils/SafeERC20.sol";
+import "../../utils/Context.sol";
 
 /**
- * @title VestingWallet
+ * @title ERC20VestingWallet
  * @dev This contract handles the vesting of ERC20 tokens for a given beneficiary. Custody of multiple tokens can be
  * given to this contract, which will release the token to the beneficiary following a given vesting schedule. The
  * vesting schedule is customizable through the {vestedAmount} function.
  *
  * Any token transferred to this contract will follow the vesting schedule as if they were locked from the beginning.
  * Consequently, if the vesting has already started, any amount of tokens sent to this contract will (at least partly)
  * be immediately releasable.
- *
- * While tokens are locked, the beneficiary still has the ability to delegate the voting power potentially associated
- * with these tokens.
  */
 contract ERC20VestingWallet is Context {
     event TokensReleased(address token, uint256 amount);
@@ -73,13 +69,6 @@ contract ERC20VestingWallet is Context {
         return _released[token];
     }
 
-    /**
-     * @dev Delegate the voting right of tokens currently vesting
-     */
-    function delegate(address token, address delegatee) public virtual onlyBeneficiary() {
-        ERC20Votes(token).delegate(delegatee);
-    }
-
     /**
      * @dev Release the tokens that have already vested.
      *

test/finance/vesting/ERC20VestingWallet.test.js

@@ -0,0 +1,87 @@
+const { constants, expectEvent, expectRevert, time } = require('@openzeppelin/test-helpers');
+const { expect } = require('chai');
+
+const ERC20VotesMock = artifacts.require('ERC20VotesMock');
+const ERC20VestingWallet = artifacts.require('ERC20VestingWallet');
+
+const min = (...args) => args.slice(1).reduce((x, y) => x.lt(y) ? x : y, args[0]);
+
+contract('ERC20VestingWallet', function (accounts) {
+  const [ beneficiary, other ] = accounts;
+
+  const amount = web3.utils.toBN(web3.utils.toWei('100'));
+  const duration = web3.utils.toBN(4 * 365 * 86400); // 4 years
+
+  beforeEach(async function () {
+    this.start = (await time.latest()).addn(3600); // in 1 hour
+    this.token = await ERC20VotesMock.new('Name', 'Symbol');
+    this.vesting = await ERC20VestingWallet.new(beneficiary, this.start, duration);
+    await this.token.mint(this.vesting.address, amount);
+
+    this.schedule = Array(256).fill()
+      .map((_, i) => web3.utils.toBN(i).mul(duration).divn(224).add(this.start))
+      .map(timestamp => ({
+        timestamp,
+        vested: min(amount, amount.mul(timestamp.sub(this.start)).div(duration)),
+      }));
+  });
+
+  it('rejects zero address for beneficiary', async function () {
+    await expectRevert(
+      ERC20VestingWallet.new(constants.ZERO_ADDRESS, this.start, duration),
+      'ERC20VestingWallet: beneficiary is zero address',
+    );
+  });
+
+  it('check vesting contract', async function () {
+    expect(await this.vesting.beneficiary()).to.be.equal(beneficiary);
+    expect(await this.vesting.start()).to.be.bignumber.equal(this.start);
+    expect(await this.vesting.duration()).to.be.bignumber.equal(duration);
+  });
+
+  describe('vesting schedule', function () {
+    it('check vesting schedule', async function () {
+      for (const { timestamp, vested } of this.schedule) {
+        expect(await this.vesting.vestedAmount(this.token.address, timestamp)).to.be.bignumber.equal(vested);
+      }
+    });
+
+    it('execute vesting schedule', async function () {
+      const { tx } = await this.vesting.release(this.token.address);
+      await expectEvent.inTransaction(tx, this.vesting, 'TokensReleased', {
+        token: this.token.address,
+        amount: '0',
+      });
+      await expectEvent.inTransaction(tx, this.token, 'Transfer', {
+        from: this.vesting.address,
+        to: beneficiary,
+        value: '0',
+      });
+
+      // on schedule
+      let released = web3.utils.toBN(0);
+      for (const { timestamp, vested } of this.schedule) {
+        await new Promise(resolve => web3.currentProvider.send({
+          method: 'evm_setNextBlockTimestamp',
+          params: [ timestamp.toNumber() ],
+        }, resolve));
+
+        const { tx } = await this.vesting.release(this.token.address);
+        await expectEvent.inTransaction(tx, this.vesting, 'TokensReleased', {
+          token: this.token.address,
+          amount: vested.sub(released),
+        });
+        await expectEvent.inTransaction(tx, this.token, 'Transfer', {
+          from: this.vesting.address,
+          to: beneficiary,
+          value: vested.sub(released),
+        });
+
+        released = vested;
+
+        expect(await this.token.balanceOf(this.vesting.address)).to.be.bignumber.equal(amount.sub(vested));
+        expect(await this.token.balanceOf(beneficiary)).to.be.bignumber.equal(vested);
+      }
+    });
+  });
+});

test/finance/ERC20VestingWallet.test.js → test/finance/vesting/ERC20VestingWalletVoting.test.js

@@ -2,11 +2,11 @@ const { constants, expectEvent, expectRevert, time } = require('@openzeppelin/te
 const { expect } = require('chai');
 
 const ERC20VotesMock = artifacts.require('ERC20VotesMock');
-const ERC20VestingWallet = artifacts.require('ERC20VestingWallet');
+const ERC20VestingWalletVoting = artifacts.require('ERC20VestingWalletVoting');
 
 const min = (...args) => args.slice(1).reduce((x, y) => x.lt(y) ? x : y, args[0]);
 
-contract('ERC20VestingWallet', function (accounts) {
+contract('ERC20VestingWalletVoting', function (accounts) {
   const [ beneficiary, other ] = accounts;
 
   const amount = web3.utils.toBN(web3.utils.toWei('100'));
@@ -15,7 +15,7 @@ contract('ERC20VestingWallet', function (accounts) {
   beforeEach(async function () {
     this.start = (await time.latest()).addn(3600); // in 1 hour
     this.token = await ERC20VotesMock.new('Name', 'Symbol');
-    this.vesting = await ERC20VestingWallet.new(beneficiary, this.start, duration);
+    this.vesting = await ERC20VestingWalletVoting.new(beneficiary, this.start, duration);
     await this.token.mint(this.vesting.address, amount);
 
     this.schedule = Array(256).fill()
@@ -28,7 +28,7 @@ contract('ERC20VestingWallet', function (accounts) {
 
   it('rejects zero address for beneficiary', async function () {
     await expectRevert(
-      ERC20VestingWallet.new(constants.ZERO_ADDRESS, this.start, duration),
+      ERC20VestingWalletVoting.new(constants.ZERO_ADDRESS, this.start, duration),
       'ERC20VestingWallet: beneficiary is zero address',
     );
   });