Merge pull request #417 from abarmat/feature-splitpayment-contract

Feature SplitPayment contract

contracts/payment/SplitPayment.sol

+pragma solidity ^0.4.11;
+
+import '../math/SafeMath.sol';
+
+/**
+ * @title SplitPayment
+ * @dev Base contract that supports multiple payees claiming funds sent to this contract 
+ * according to the proportion they own.
+ */
+contract SplitPayment {
+  using SafeMath for uint256;
+
+  uint256 public totalShares = 0;
+  uint256 public totalReleased = 0;
+
+  mapping(address => uint256) public shares;
+  mapping(address => uint256) public released;
+  address[] public payees;
+
+  /**
+   * @dev Constructor
+   */
+  function SplitPayment(address[] _payees, uint256[] _shares) {
+    require(_payees.length == _shares.length);
+
+    for (uint256 i = 0; i < _payees.length; i++) {
+      addPayee(_payees[i], _shares[i]);
+    }
+  }
+
+  /**
+   * @dev Add a new payee to the contract.
+   * @param _payee The address of the payee to add.
+   * @param _shares The number of shares owned by the payee.
+   */
+  function addPayee(address _payee, uint256 _shares) internal {
+    require(_payee != address(0));
+    require(_shares > 0);
+    require(shares[_payee] == 0);
+
+    payees.push(_payee);
+    shares[_payee] = _shares;
+    totalShares = totalShares.add(_shares);
+  }
+
+  /**
+   * @dev Claim your share of the balance.
+   */
+  function claim() public {
+    address payee = msg.sender;
+
+    require(shares[payee] > 0);
+
+    uint256 totalReceived = this.balance.add(totalReleased);
+    uint256 payment = totalReceived.mul(shares[payee]).div(totalShares).sub(released[payee]);
+
+    require(payment != 0);
+    require(this.balance >= payment);
+
+    released[payee] = released[payee].add(payment);
+    totalReleased = totalReleased.add(payment);
+
+    payee.transfer(payment);
+  }
+}

test/SplitPayment.js

+const BigNumber = web3.BigNumber
+
+const should = require('chai')
+  .use(require('chai-as-promised'))
+  .use(require('chai-bignumber')(BigNumber))
+  .should()
+
+const EVMThrow = require('./helpers/EVMThrow.js')
+const SplitPaymentMock = artifacts.require('./helpers/SplitPaymentMock.sol')
+
+contract('SplitPayment', function ([owner, payee1, payee2, payee3, nonpayee1, payer1]) {
+  const amount = web3.toWei(1.0, 'ether')
+
+  beforeEach(async function () {
+    this.payees = [payee1, payee2, payee3]
+    this.shares = [20, 10, 70]
+
+    this.contract = await SplitPaymentMock.new(this.payees, this.shares)
+  })
+
+  it('should accept payments', async function () {
+    await web3.eth.sendTransaction({ from: owner, to: this.contract.address, value: amount })
+
+    const balance = web3.eth.getBalance(this.contract.address)
+    balance.should.be.bignumber.equal(amount)
+  })
+
+  it('should store shares if address is payee', async function () {
+    const shares = await this.contract.shares.call(payee1)
+    shares.should.be.bignumber.not.equal(0)
+  })
+
+  it('should not store shares if address is not payee', async function () {
+    const shares = await this.contract.shares.call(nonpayee1)
+    shares.should.be.bignumber.equal(0)
+  })
+
+  it('should throw if no funds to claim', async function () {
+    await this.contract.claim({from: payee1}).should.be.rejectedWith(EVMThrow)
+  })
+
+  it('should throw if non-payee want to claim', async function () {
+    await web3.eth.sendTransaction({from: payer1, to: this.contract.address, value: amount})
+    await this.contract.claim({from: nonpayee1}).should.be.rejectedWith(EVMThrow)
+  })
+  
+  it('should distribute funds to payees', async function () {
+    await web3.eth.sendTransaction({from: payer1, to: this.contract.address, value: amount})
+
+    // receive funds
+    const initBalance = web3.eth.getBalance(this.contract.address)
+    initBalance.should.be.bignumber.equal(amount)
+
+    // distribute to payees
+    const initAmount1 = web3.eth.getBalance(payee1)
+    await this.contract.claim({from: payee1})
+    const profit1 = web3.eth.getBalance(payee1) - initAmount1
+    assert(Math.abs(profit1 - web3.toWei(0.20, 'ether')) < 1e16)
+
+    const initAmount2 = web3.eth.getBalance(payee2)
+    await this.contract.claim({from: payee2})
+    const profit2 = web3.eth.getBalance(payee2) - initAmount2
+    assert(Math.abs(profit2 - web3.toWei(0.10, 'ether')) < 1e16)
+
+    const initAmount3 = web3.eth.getBalance(payee3)
+    await this.contract.claim({from: payee3})
+    const profit3 = web3.eth.getBalance(payee3) - initAmount3
+    assert(Math.abs(profit3 - web3.toWei(0.70, 'ether')) < 1e16)
+
+    // end balance should be zero
+    const endBalance = web3.eth.getBalance(this.contract.address)
+    endBalance.should.be.bignumber.equal(0)
+
+    // check correct funds released accounting
+    const totalReleased = await this.contract.totalReleased.call()
+    totalReleased.should.be.bignumber.equal(initBalance)
+  })
+})

test/helpers/SplitPaymentMock.sol

+pragma solidity ^0.4.11;
+
+import '../../contracts/payment/SplitPayment.sol';
+
+// mock class using SplitPayment
+contract SplitPaymentMock is SplitPayment {
+  function SplitPaymentMock(address[] _payees, uint256[] _shares) 
+    SplitPayment(_payees, _shares) payable {}
+  function () payable {}
+}