Merge pull request #342 from jakub-wojciechowski/master

Add complex crowdsale example #331

contracts/examples/SampleCrowdsale.sol

+pragma solidity ^0.4.11;
+
+import "../crowdsale/CappedCrowdsale.sol";
+import "../crowdsale/RefundableCrowdsale.sol";
+import "../token/MintableToken.sol";
+
+/**
+ * @title SampleCrowdsaleToken
+ * @dev Very simple ERC20 Token that can be minted.
+ * It is meant to be used in a crowdsale contract.
+ */
+contract SampleCrowdsaleToken is MintableToken {
+
+  string public constant name = "Sample Crowdsale Token";
+  string public constant symbol = "SCT";
+  uint8 public constant decimals = 18;
+
+}
+
+/**
+ * @title SampleCrowdsale
+ * @dev This is an example of a fully fledged crowdsale.
+ * The way to add new features to a base crowdsale is by multiple inheritance.
+ * In this example we are providing following extensions:
+ * CappedCrowdsale - sets a max boundary for raised funds
+ * RefundableCrowdsale - set a min goal to be reached and returns funds if it's not met
+ *
+ * After adding multiple features it's good practice to run integration tests
+ * to ensure that subcontracts works together as intended.
+ */
+contract SampleCrowdsale is CappedCrowdsale, RefundableCrowdsale {
+
+  function SampleCrowdsale(uint256 _startBlock, uint256 _endBlock, uint256 _rate, uint256 _goal, uint256 _cap, address _wallet)
+    CappedCrowdsale(_cap)
+    FinalizableCrowdsale()
+    RefundableCrowdsale(_goal)
+    Crowdsale(_startBlock, _endBlock, _rate, _wallet)
+  {
+    //As goal needs to be met for a successful crowdsale
+    //the value needs to less or equal than a cap which is limit for accepted funds
+    require(_goal <= _cap);
+  }
+
+  function createTokenContract() internal returns (MintableToken) {
+    return new SampleCrowdsaleToken();
+  }
+
+}
\ No newline at end of file

test/SampleCrowdsale.js

+import ether from './helpers/ether'
+import advanceToBlock from './helpers/advanceToBlock'
+import EVMThrow from './helpers/EVMThrow'
+
+const BigNumber = web3.BigNumber;
+
+const should = require('chai')
+  .use(require('chai-as-promised'))
+  .use(require('chai-bignumber')(BigNumber))
+  .should();
+
+const SampleCrowdsale = artifacts.require('SampleCrowdsale');
+const SampleCrowdsaleToken = artifacts.require('SampleCrowdsaleToken');
+
+contract('Crowdsale', function ([owner, wallet, investor]) {
+
+  const RATE = new BigNumber(10);
+  const GOAL = ether(10);
+  const CAP  = ether(20);
+
+  beforeEach(async function () {
+    this.startBlock = web3.eth.blockNumber + 10;
+    this.endBlock =   web3.eth.blockNumber + 20;
+
+    this.crowdsale = await SampleCrowdsale.new(this.startBlock, this.endBlock, RATE, GOAL, CAP, wallet);
+    this.token = SampleCrowdsaleToken.at(await this.crowdsale.token());
+  });
+
+  
+  it('should create crowdsale with correct parameters', async function () {
+    this.crowdsale.should.exist;
+    this.token.should.exist;
+
+    (await this.crowdsale.startBlock()).should.be.bignumber.equal(this.startBlock);
+    (await this.crowdsale.endBlock()).should.be.bignumber.equal(this.endBlock);
+    (await this.crowdsale.rate()).should.be.bignumber.equal(RATE);
+    (await this.crowdsale.wallet()).should.be.equal(wallet);
+    (await this.crowdsale.goal()).should.be.bignumber.equal(GOAL);
+    (await this.crowdsale.cap()).should.be.bignumber.equal(CAP);
+  });
+
+  it('should not accept payments before start', async function () {
+    await this.crowdsale.send(ether(1)).should.be.rejectedWith(EVMThrow);
+    await this.crowdsale.buyTokens(investor, {from: investor, value: ether(1)}).should.be.rejectedWith(EVMThrow);
+  });
+
+  it('should accept payments during the sale', async function () {
+    const investmentAmount = ether(1);
+    const expectedTokenAmount = RATE.mul(investmentAmount);
+
+    await advanceToBlock(this.startBlock - 1);
+    await this.crowdsale.buyTokens(investor, {value: investmentAmount, from: investor}).should.be.fulfilled;
+
+    (await this.token.balanceOf(investor)).should.be.bignumber.equal(expectedTokenAmount);
+    (await this.token.totalSupply()).should.be.bignumber.equal(expectedTokenAmount);
+  });
+
+  it('should reject payments after end', async function () {
+    await advanceToBlock(this.endBlock);
+    await this.crowdsale.send(ether(1)).should.be.rejectedWith(EVMThrow);
+    await this.crowdsale.buyTokens(investor, {value: ether(1), from: investor}).should.be.rejectedWith(EVMThrow);
+  });
+
+  it('should reject payments over cap', async function () {
+    await advanceToBlock(this.startBlock - 1);
+    await this.crowdsale.send(CAP);
+    await this.crowdsale.send(1).should.be.rejectedWith(EVMThrow);
+  });
+
+  it('should allow finalization and transfer funds to wallet if the goal is reached', async function () {
+    await advanceToBlock(this.endBlock - 1);
+    await this.crowdsale.send(GOAL);
+
+    const beforeFinalization = web3.eth.getBalance(wallet);
+    await this.crowdsale.finalize({from: owner});
+    const afterFinalization = web3.eth.getBalance(wallet);
+
+    afterFinalization.minus(beforeFinalization).should.be.bignumber.equal(GOAL);
+  });
+
+  it('should allow refunds if the goal is not reached', async function () {
+    const balanceBeforeInvestment = web3.eth.getBalance(investor);
+
+    await advanceToBlock(this.startBlock - 1);
+    await this.crowdsale.sendTransaction({value: ether(1), from: investor, gasPrice: 0});
+    await advanceToBlock(this.endBlock);
+
+    await this.crowdsale.finalize({from: owner});
+    await this.crowdsale.claimRefund({from: investor, gasPrice: 0}).should.be.fulfilled;
+
+    const balanceAfterRefund = web3.eth.getBalance(investor);
+    balanceBeforeInvestment.should.be.bignumber.equal(balanceAfterRefund);
+  });
+
+});