Merge pull request #476 from martriay/add-token-vesting

Add token vesting

contracts/token/LimitedTransferToken.sol

@@ -1,57 +0,0 @@
-pragma solidity ^0.4.11;
-
-import "./ERC20.sol";
-
-/**
- * @title LimitedTransferToken
- * @dev LimitedTransferToken defines the generic interface and the implementation to limit token
- * transferability for different events. It is intended to be used as a base class for other token
- * contracts.
- * LimitedTransferToken has been designed to allow for different limiting factors,
- * this can be achieved by recursively calling super.transferableTokens() until the base class is
- * hit. For example:
- *     function transferableTokens(address holder, uint64 time) constant public returns (uint256) {
- *       return min256(unlockedTokens, super.transferableTokens(holder, time));
- *     }
- * A working example is VestedToken.sol:
- * https://github.com/OpenZeppelin/zeppelin-solidity/blob/master/contracts/token/VestedToken.sol
- */
-
-contract LimitedTransferToken is ERC20 {
-
-  /**
-   * @dev Checks whether it can transfer or otherwise throws.
-   */
-  modifier canTransfer(address _sender, uint256 _value) {
-   require(_value <= transferableTokens(_sender, uint64(now)));
-   _;
-  }
-
-  /**
-   * @dev Checks modifier and allows transfer if tokens are not locked.
-   * @param _to The address that will receive the tokens.
-   * @param _value The amount of tokens to be transferred.
-   */
-  function transfer(address _to, uint256 _value) canTransfer(msg.sender, _value) public returns (bool) {
-    return super.transfer(_to, _value);
-  }
-
-  /**
-  * @dev Checks modifier and allows transfer if tokens are not locked.
-  * @param _from The address that will send the tokens.
-  * @param _to The address that will receive the tokens.
-  * @param _value The amount of tokens to be transferred.
-  */
-  function transferFrom(address _from, address _to, uint256 _value) canTransfer(_from, _value) public returns (bool) {
-    return super.transferFrom(_from, _to, _value);
-  }
-
-  /**
-   * @dev Default transferable tokens function returns all tokens for a holder (no limit).
-   * @dev Overwriting transferableTokens(address holder, uint64 time) is the way to provide the
-   * specific logic for limiting token transferability for a holder over time.
-   */
-  function transferableTokens(address holder, uint64 time) public constant returns (uint256) {
-    return balanceOf(holder);
-  }
-}

contracts/token/TokenVesting.sol

@@ -0,0 +1,103 @@
+pragma solidity ^0.4.11;
+
+import './ERC20Basic.sol';
+import '../ownership/Ownable.sol';
+import '../math/Math.sol';
+import '../math/SafeMath.sol';
+
+/**
+ * @title TokenVesting
+ * @dev A token holder contract that can release its token balance gradually like a
+ * typical vesting scheme, with a cliff and vesting period. Optionally revocable by the
+ * owner.
+ */
+contract TokenVesting is Ownable {
+  using SafeMath for uint256;
+
+  event Released(uint256 amount);
+  event Revoked();
+
+  // beneficiary of tokens after they are released
+  address beneficiary;
+
+  uint256 cliff;
+  uint256 start;
+  uint256 duration;
+
+  bool revocable;
+
+  mapping (address => uint256) released;
+
+  /**
+   * @dev Creates a vesting contract that vests its balance of any ERC20 token to the
+   * _beneficiary, gradually in a linear fashion until _start + _duration. By then all
+   * of the balance will have vested.
+   * @param _beneficiary address of the beneficiary to whom vested tokens are transferred
+   * @param _cliff duration in seconds of the cliff in which tokens will begin to vest
+   * @param _duration duration in seconds of the period in which the tokens will vest
+   * @param _revocable whether the vesting is revocable or not
+   */
+  function TokenVesting(address _beneficiary, uint256 _start, uint256 _cliff, uint256 _duration, bool _revocable) {
+    require(_beneficiary != 0x0);
+    require(_cliff <= _duration);
+
+    beneficiary = _beneficiary;
+    revocable = _revocable;
+    duration = _duration;
+    cliff = _start + _cliff;
+    start = _start;
+  }
+
+  /**
+   * @notice Transfers vested tokens to beneficiary.
+   * @param token ERC20 token which is being vested
+   */
+  function release(ERC20Basic token) {
+    uint256 vested = vestedAmount(token);
+
+    require(vested > 0);
+
+    token.transfer(beneficiary, vested);
+
+    released[token] = released[token].add(vested);
+
+    Released(vested);
+  }
+
+  /**
+   * @notice Allows the owner to revoke the vesting. Tokens already vested remain in the contract.
+   * @param token ERC20 token which is being vested
+   */
+  function revoke(ERC20Basic token) onlyOwner {
+    require(revocable);
+
+    uint256 balance = token.balanceOf(this);
+
+    uint256 vested = vestedAmount(token);
+
+    token.transfer(owner, balance - vested);
+
+    Revoked();
+  }
+
+  /**
+   * @dev Calculates the amount that has already vested but hasn't been released yet.
+   * @param token ERC20 token which is being vested
+   */
+  function vestedAmount(ERC20Basic token) constant returns (uint256) {
+    if (now < cliff) {
+      return 0;
+    } else if (now >= start + duration) {
+      return token.balanceOf(this);
+    } else {
+      uint256 currentBalance = token.balanceOf(this);
+      uint256 totalBalance = currentBalance.add(released[token]);
+
+      uint256 vested = totalBalance.mul(now - start).div(duration);
+      uint256 unreleased = vested.sub(released[token]);
+
+      // currentBalance can be 0 in case of vesting being revoked earlier.
+      return Math.min256(currentBalance, unreleased);
+    }
+  }
+}

contracts/token/VestedToken.sol

@@ -1,241 +0,0 @@
-pragma solidity ^0.4.11;
-
-import "../math/Math.sol";
-import "./StandardToken.sol";
-import "./LimitedTransferToken.sol";
-
-/**
- * @title Vested token
- * @dev Tokens that can be vested for a group of addresses.
- */
-contract VestedToken is StandardToken, LimitedTransferToken {
-
-  uint256 MAX_GRANTS_PER_ADDRESS = 20;
-
-  struct TokenGrant {
-    address granter;     // 20 bytes
-    uint256 value;       // 32 bytes
-    uint64 cliff;
-    uint64 vesting;
-    uint64 start;        // 3 * 8 = 24 bytes
-    bool revokable;
-    bool burnsOnRevoke;  // 2 * 1 = 2 bits? or 2 bytes?
-  } // total 78 bytes = 3 sstore per operation (32 per sstore)
-
-  mapping (address => TokenGrant[]) public grants;
-
-  event NewTokenGrant(address indexed from, address indexed to, uint256 value, uint256 grantId);
-
-  /**
-   * @dev Grant tokens to a specified address
-   * @param _to address The address which the tokens will be granted to.
-   * @param _value uint256 The amount of tokens to be granted.
-   * @param _start uint64 Time of the beginning of the grant.
-   * @param _cliff uint64 Time of the cliff period.
-   * @param _vesting uint64 The vesting period.
-   */
-  function grantVestedTokens(
-    address _to,
-    uint256 _value,
-    uint64 _start,
-    uint64 _cliff,
-    uint64 _vesting,
-    bool _revokable,
-    bool _burnsOnRevoke
-  ) public {
-
-    // Check for date inconsistencies that may cause unexpected behavior
-    require(_cliff >= _start && _vesting >= _cliff);
-
-    require(tokenGrantsCount(_to) < MAX_GRANTS_PER_ADDRESS);   // To prevent a user being spammed and have his balance locked (out of gas attack when calculating vesting).
-
-    uint256 count = grants[_to].push(
-                TokenGrant(
-                  _revokable ? msg.sender : 0, // avoid storing an extra 20 bytes when it is non-revokable
-                  _value,
-                  _cliff,
-                  _vesting,
-                  _start,
-                  _revokable,
-                  _burnsOnRevoke
-                )
-              );
-
-    transfer(_to, _value);
-
-    NewTokenGrant(msg.sender, _to, _value, count - 1);
-  }
-
-  /**
-   * @dev Revoke the grant of tokens of a specifed address.
-   * @param _holder The address which will have its tokens revoked.
-   * @param _grantId The id of the token grant.
-   */
-  function revokeTokenGrant(address _holder, uint256 _grantId) public {
-    TokenGrant storage grant = grants[_holder][_grantId];
-
-    require(grant.revokable);
-    require(grant.granter == msg.sender); // Only granter can revoke it
-
-    address receiver = grant.burnsOnRevoke ? 0xdead : msg.sender;
-
-    uint256 nonVested = nonVestedTokens(grant, uint64(now));
-
-    // remove grant from array
-    delete grants[_holder][_grantId];
-    grants[_holder][_grantId] = grants[_holder][grants[_holder].length.sub(1)];
-    grants[_holder].length -= 1;
-
-    balances[receiver] = balances[receiver].add(nonVested);
-    balances[_holder] = balances[_holder].sub(nonVested);
-
-    Transfer(_holder, receiver, nonVested);
-  }
-
-
-  /**
-   * @dev Calculate the total amount of transferable tokens of a holder at a given time
-   * @param holder address The address of the holder
-   * @param time uint64 The specific time.
-   * @return An uint256 representing a holder's total amount of transferable tokens.
-   */
-  function transferableTokens(address holder, uint64 time) public constant returns (uint256) {
-    uint256 grantIndex = tokenGrantsCount(holder);
-
-    if (grantIndex == 0) return super.transferableTokens(holder, time); // shortcut for holder without grants
-
-    // Iterate through all the grants the holder has, and add all non-vested tokens
-    uint256 nonVested = 0;
-    for (uint256 i = 0; i < grantIndex; i++) {
-      nonVested = SafeMath.add(nonVested, nonVestedTokens(grants[holder][i], time));
-    }
-
-    // Balance - totalNonVested is the amount of tokens a holder can transfer at any given time
-    uint256 vestedTransferable = SafeMath.sub(balanceOf(holder), nonVested);
-
-    // Return the minimum of how many vested can transfer and other value
-    // in case there are other limiting transferability factors (default is balanceOf)
-    return Math.min256(vestedTransferable, super.transferableTokens(holder, time));
-  }
-
-  /**
-   * @dev Check the amount of grants that an address has.
-   * @param _holder The holder of the grants.
-   * @return A uint256 representing the total amount of grants.
-   */
-  function tokenGrantsCount(address _holder) public constant returns (uint256 index) {
-    return grants[_holder].length;
-  }
-
-  /**
-   * @dev Calculate amount of vested tokens at a specific time
-   * @param tokens uint256 The amount of tokens granted
-   * @param time uint64 The time to be checked
-   * @param start uint64 The time representing the beginning of the grant
-   * @param cliff uint64  The cliff period, the period before nothing can be paid out
-   * @param vesting uint64 The vesting period
-   * @return An uint256 representing the amount of vested tokens of a specific grant
-   *  transferableTokens
-   *   |                         _/--------   vestedTokens rect
-   *   |                       _/
-   *   |                     _/
-   *   |                   _/
-   *   |                 _/
-   *   |                /
-   *   |              .|
-   *   |            .  |
-   *   |          .    |
-   *   |        .      |
-   *   |      .        |
-   *   |    .          |
-   *   +===+===========+---------+----------> time
-   *      Start       Cliff    Vesting
-   */
-  function calculateVestedTokens(
-    uint256 tokens,
-    uint256 time,
-    uint256 start,
-    uint256 cliff,
-    uint256 vesting) public constant returns (uint256)
-    {
-      // Shortcuts for before cliff and after vesting cases.
-      if (time < cliff) return 0;
-      if (time >= vesting) return tokens;
-
-      // Interpolate all vested tokens.
-      // As before cliff the shortcut returns 0, we can use just calculate a value
-      // in the vesting rect (as shown in above's figure)
-
-      // vestedTokens = (tokens * (time - start)) / (vesting - start)
-      uint256 vestedTokens = SafeMath.div(
-                                    SafeMath.mul(
-                                      tokens,
-                                      SafeMath.sub(time, start)
-                                      ),
-                                    SafeMath.sub(vesting, start)
-                                    );
-
-      return vestedTokens;
-  }
-
-  /**
-   * @dev Get all information about a specific grant.
-   * @param _holder The address which will have its tokens revoked.
-   * @param _grantId The id of the token grant.
-   * @return Returns all the values that represent a TokenGrant(address, value, start, cliff,
-   * revokability, burnsOnRevoke, and vesting) plus the vested value at the current time.
-   */
-  function tokenGrant(address _holder, uint256 _grantId) public constant returns (address granter, uint256 value, uint256 vested, uint64 start, uint64 cliff, uint64 vesting, bool revokable, bool burnsOnRevoke) {
-    TokenGrant storage grant = grants[_holder][_grantId];
-
-    granter = grant.granter;
-    value = grant.value;
-    start = grant.start;
-    cliff = grant.cliff;
-    vesting = grant.vesting;
-    revokable = grant.revokable;
-    burnsOnRevoke = grant.burnsOnRevoke;
-
-    vested = vestedTokens(grant, uint64(now));
-  }
-
-  /**
-   * @dev Get the amount of vested tokens at a specific time.
-   * @param grant TokenGrant The grant to be checked.
-   * @param time The time to be checked
-   * @return An uint256 representing the amount of vested tokens of a specific grant at a specific time.
-   */
-  function vestedTokens(TokenGrant grant, uint64 time) private constant returns (uint256) {
-    return calculateVestedTokens(
-      grant.value,
-      uint256(time),
-      uint256(grant.start),
-      uint256(grant.cliff),
-      uint256(grant.vesting)
-    );
-  }
-
-  /**
-   * @dev Calculate the amount of non vested tokens at a specific time.
-   * @param grant TokenGrant The grant to be checked.
-   * @param time uint64 The time to be checked
-   * @return An uint256 representing the amount of non vested tokens of a specific grant on the
-   * passed time frame.
-   */
-  function nonVestedTokens(TokenGrant grant, uint64 time) private constant returns (uint256) {
-    return grant.value.sub(vestedTokens(grant, time));
-  }
-
-  /**
-   * @dev Calculate the date when the holder can transfer all its tokens
-   * @param holder address The address of the holder
-   * @return An uint256 representing the date of the last transferable tokens.
-   */
-  function lastTokenIsTransferableDate(address holder) public constant returns (uint64 date) {
-    date = uint64(now);
-    uint256 grantIndex = grants[holder].length;
-    for (uint256 i = 0; i < grantIndex; i++) {
-      date = Math.max64(grants[holder][i].vesting, date);
-    }
-  }
-}

test/TokenVesting.js

@@ -0,0 +1,107 @@
+const BigNumber = web3.BigNumber
+
+require('chai')
+  .use(require('chai-as-promised'))
+  .use(require('chai-bignumber')(BigNumber))
+  .should();
+
+import EVMThrow from './helpers/EVMThrow'
+import latestTime from './helpers/latestTime';
+import {increaseTimeTo, duration} from './helpers/increaseTime';
+
+const MintableToken = artifacts.require('MintableToken');
+const TokenVesting = artifacts.require('TokenVesting');
+
+contract('TokenVesting', function ([_, owner, beneficiary]) {
+
+  const amount = new BigNumber(1000);
+
+  beforeEach(async function () {
+    this.token = await MintableToken.new({ from: owner });
+
+    this.start = latestTime() + duration.minutes(1); // +1 minute so it starts after contract instantiation
+    this.cliff = duration.years(1);
+    this.duration = duration.years(2);
+
+    this.vesting = await TokenVesting.new(beneficiary, this.start, this.cliff, this.duration, true, { from: owner });
+
+    await this.token.mint(this.vesting.address, amount, { from: owner });
+  });
+
+  it('cannot be released before cliff', async function () {
+    await this.vesting.release(this.token.address).should.be.rejectedWith(EVMThrow);
+  });
+
+  it('can be released after cliff', async function () {
+    await increaseTimeTo(this.start + this.cliff + duration.weeks(1));
+    await this.vesting.release(this.token.address).should.be.fulfilled;
+  });
+
+  it('should release proper amount after cliff', async function () {
+    await increaseTimeTo(this.start + this.cliff);
+
+    const { receipt } = await this.vesting.release(this.token.address);
+    const releaseTime = web3.eth.getBlock(receipt.blockNumber).timestamp;
+
+    const balance = await this.token.balanceOf(beneficiary);
+    balance.should.bignumber.equal(amount.mul(releaseTime - this.start).div(this.duration).floor());
+  });
+
+  it('should linearly release tokens during vesting period', async function () {
+    const vestingPeriod = this.duration - this.cliff;
+    const checkpoints = 4;
+
+    for (let i = 1; i <= checkpoints; i++) {
+      const now = this.start + this.cliff + i * (vestingPeriod / checkpoints);
+      await increaseTimeTo(now);
+
+      await this.vesting.release(this.token.address);
+      const balance = await this.token.balanceOf(beneficiary);
+      const expectedVesting = amount.mul(now - this.start).div(this.duration).floor();
+
+      balance.should.bignumber.equal(expectedVesting);
+    }
+  });
+
+  it('should have released all after end', async function () {
+    await increaseTimeTo(this.start + this.duration);
+    await this.vesting.release(this.token.address);
+    const balance = await this.token.balanceOf(beneficiary);
+    balance.should.bignumber.equal(amount);
+  });
+
+  it('should be revoked by owner if revocable is set', async function () {
+    await this.vesting.revoke(this.token.address, { from: owner }).should.be.fulfilled;
+  });
+
+  it('should fail to be revoked by owner if revocable not set', async function () {
+    const vesting = await TokenVesting.new(beneficiary, this.start, this.cliff, this.duration, false, { from: owner } );
+    await vesting.revoke(this.token.address, { from: owner }).should.be.rejectedWith(EVMThrow);
+  });
+
+  it('should return the non-vested tokens when revoked by owner', async function () {
+    await increaseTimeTo(this.start + this.cliff + duration.weeks(1));
+    await this.vesting.release(this.token.address);
+
+    const vested = await this.vesting.vestedAmount(this.token.address);
+    const balance = await this.token.balanceOf(this.vesting.address);
+
+    await this.vesting.revoke(this.token.address, { from: owner });
+
+    const ownerBalance = await this.token.balanceOf(owner);
+    ownerBalance.should.bignumber.equal(balance.sub(vested));
+  });
+
+  it('should keep the vested tokens when revoked by owner', async function () {
+    await increaseTimeTo(this.start + this.cliff + duration.weeks(1));
+    await this.vesting.release(this.token.address);
+
+    const vested = await this.vesting.vestedAmount(this.token.address);
+
+    await this.vesting.revoke(this.token.address, { from: owner });
+
+    const balance = await this.token.balanceOf(this.vesting.address);
+    balance.should.bignumber.equal(vested);
+  });
+
+});

test/VestedToken.js

@@ -1,175 +0,0 @@
-const assertJump = require('./helpers/assertJump');
-const timer = require('./helpers/timer');
-var VestedTokenMock = artifacts.require("./helpers/VestedTokenMock.sol");
-
-contract('VestedToken', function(accounts) {
-  let token = null
-  let now = 0
-
-  const tokenAmount = 50
-
-  const granter = accounts[0]
-  const receiver = accounts[1]
-
-  beforeEach(async () => {
-    token = await VestedTokenMock.new(granter, 100);
-    now = web3.eth.getBlock(web3.eth.blockNumber).timestamp;
-  })
-
-  it('granter can grant tokens without vesting', async () => {
-    await token.transfer(receiver, tokenAmount, { from: granter })
-
-    assert.equal(await token.balanceOf(receiver), tokenAmount);
-    assert.equal(await token.transferableTokens(receiver, now), tokenAmount);
-  })
-
-  describe('getting a revokable/non-burnable token grant', async () => {
-    const cliff = 10000
-    const vesting = 20000 // seconds
-
-    beforeEach(async () => {
-      await token.grantVestedTokens(receiver, tokenAmount, now, now + cliff, now + vesting, true, false, { from: granter })
-    })
-
-    it('tokens are received', async () => {
-      assert.equal(await token.balanceOf(receiver), tokenAmount);
-    })
-
-    it('has 0 transferable tokens before cliff', async () => {
-      assert.equal(await token.transferableTokens(receiver, now), 0);
-    })
-
-    it('all tokens are transferable after vesting', async () => {
-      assert.equal(await token.transferableTokens(receiver, now + vesting), tokenAmount);
-    })
-
-    it('throws when trying to transfer non vested tokens', async () => {
-      try {
-        await token.transfer(accounts[7], 1, { from: receiver })
-        assert.fail('should have thrown before');
-      } catch(error) {
-        assertJump(error);
-      }
-    })
-
-    it('throws when trying to transfer from non vested tokens', async () => {
-      try {
-        await token.approve(accounts[7], 1, { from: receiver })
-        await token.transferFrom(receiver, accounts[7], tokenAmount, { from: accounts[7] })
-        assert.fail('should have thrown before');
-      } catch(error) {
-        assertJump(error);
-      }
-    })
-
-    it('can be revoked by granter', async () => {
-      await token.revokeTokenGrant(receiver, 0, { from: granter });
-      assert.equal(await token.balanceOf(receiver), 0);
-      assert.equal(await token.balanceOf(granter), 100);
-    })
-
-    it('cannot be revoked by non granter', async () => {
-      try {
-        await token.revokeTokenGrant(receiver, 0, { from: accounts[3] });
-        assert.fail('should have thrown before');
-      } catch(error) {
-        assertJump(error);
-      }
-    })
-
-    it('can be revoked by granter and non vested tokens are returned', async () => {
-      await timer(cliff);
-      await token.revokeTokenGrant(receiver, 0, { from: granter });
-      assert.equal(await token.balanceOf(receiver), tokenAmount * cliff / vesting);
-    })
-
-    it('can transfer all tokens after vesting ends', async () => {
-      await timer(vesting);
-      await token.transfer(accounts[7], tokenAmount, { from: receiver })
-      assert.equal(await token.balanceOf(accounts[7]), tokenAmount);
-    })
-
-    it('can approve and transferFrom all tokens after vesting ends', async () => {
-      await timer(vesting);
-      await token.approve(accounts[7], tokenAmount, { from: receiver })
-      await token.transferFrom(receiver, accounts[7], tokenAmount, { from: accounts[7] })
-      assert.equal(await token.balanceOf(accounts[7]), tokenAmount);
-    })
-
-    it('can handle composed vesting schedules', async () => {
-      await timer(cliff);
-      await token.transfer(accounts[7], 12, { from: receiver })
-      assert.equal(await token.balanceOf(accounts[7]), 12);
-
-      let newNow = web3.eth.getBlock(web3.eth.blockNumber).timestamp
-
-      await token.grantVestedTokens(receiver, tokenAmount, newNow, newNow + cliff, newNow + vesting, false, false, { from: granter })
-
-      await token.transfer(accounts[7], 13, { from: receiver })
-      assert.equal(await token.balanceOf(accounts[7]), tokenAmount / 2);
-
-      assert.equal(await token.balanceOf(receiver), 3 * tokenAmount / 2)
-      assert.equal(await token.transferableTokens(receiver, newNow), 0)
-      await timer(vesting);
-      await token.transfer(accounts[7], 3 * tokenAmount / 2, { from: receiver })
-      assert.equal(await token.balanceOf(accounts[7]), tokenAmount * 2)
-    })
-  })
-
-  describe('getting a non-revokable token grant', async () => {
-    const cliff = 10000
-    const vesting = 20000 // seconds
-
-    beforeEach(async () => {
-      await token.grantVestedTokens(receiver, tokenAmount, now, now + cliff, now + vesting, false, false, { from: granter })
-    })
-
-    it('tokens are received', async () => {
-      assert.equal(await token.balanceOf(receiver), tokenAmount);
-    })
-
-    it('throws when granter attempts to revoke', async () => {
-      try {
-        await token.revokeTokenGrant(receiver, 0, { from: granter });
-        assert.fail('should have thrown before');
-      } catch(error) {
-        assertJump(error);
-      }
-    })
-  })
-
-  describe('getting a revokable/burnable token grant', async () => {
-    const cliff = 100000
-    const vesting = 200000 // seconds
-    const burnAddress = '0x000000000000000000000000000000000000dead'
-
-    beforeEach(async () => {
-      await token.grantVestedTokens(receiver, tokenAmount, now, now + cliff, now + vesting, true, true, { from: granter })
-    })
-
-    it('tokens are received', async () => {
-      assert.equal(await token.balanceOf(receiver), tokenAmount);
-    })
-
-    it('can be revoked by granter and tokens are burned', async () => {
-      await token.revokeTokenGrant(receiver, 0, { from: granter });
-      assert.equal(await token.balanceOf(receiver), 0);
-      assert.equal(await token.balanceOf(burnAddress), tokenAmount);
-    })
-
-    it('cannot be revoked by non granter', async () => {
-      try {
-        await token.revokeTokenGrant(receiver, 0, { from: accounts[3] });
-        assert.fail('should have thrown before');
-      } catch(error) {
-        assertJump(error);
-      }
-    })
-
-    it('can be revoked by granter and non vested tokens are returned', async () => {
-      await timer(cliff);
-      await token.revokeTokenGrant(receiver, 0, { from: granter });
-      assert.equal(await token.balanceOf(burnAddress), tokenAmount * cliff / vesting);
-    })
-  })
-});

test/helpers/VestedTokenMock.sol

@@ -1,11 +0,0 @@
-pragma solidity ^0.4.11;
-
-import '../../contracts/token/VestedToken.sol';
-
-// mock class using StandardToken
-contract VestedTokenMock is VestedToken {
-  function VestedTokenMock(address initialAccount, uint256 initialBalance) {
-    balances[initialAccount] = initialBalance;
-    totalSupply = initialBalance;
-  }
-}