Add Question contract

Increased time cannot be reseted according to trufflesuite/ganache-cli-archive#390

truffle/contracts/Question.sol

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+pragma solidity ^0.4.15;
+
+import "./ERC20Token.sol";
+
+contract Question {
+  uint public constant version = 1;
+
+  struct Charity {
+    string name;
+    address addr;
+  }
+
+  ERC20Interface token;
+  Charity[] public charities;
+  string public question;
+  string public twitterAccount;
+  uint public deadline;
+  string public tweetUrl;
+  mapping(address => uint256) public donorDonations;
+  uint public donorCount;
+  uint256 public donations;
+
+  modifier beforeDeadline() {
+    require(now < deadline);
+    _;
+  }
+
+  function getCharitiesCount() constant returns (uint) {
+    return charities.length;
+  }
+
+  function Question(ERC20Interface _token, string _question, string _twitterAccount, uint _deadline) {
+    token = _token;
+    require(bytes(_question).length != 0);
+    require(bytes(_twitterAccount).length != 0);
+    // todo check twitter account more carefully
+    require(now < _deadline);
+
+    charities.push(Charity({ name: 'Test charity 1',
+      addr: 0xfA491DF8780761853D127A9f7b2772D688A0E3B5 }));
+    charities.push(Charity({ name: 'Test charity 2',
+      addr: 0x45992982736870Fe45c41049C5F785d4E4cc38Ec }));
+    charities.push(Charity({ name: 'Test charity 3',
+      addr: 0xfA491DF8780761853D127A9f7b2772D688A0E3B5 }));
+    charities.push(Charity({ name: 'Test charity 4',
+      addr: 0x45992982736870Fe45c41049C5F785d4E4cc38Ec }));
+
+    question = _question;
+    twitterAccount = _twitterAccount;
+    deadline = _deadline;
+  }
+
+  function increase(uint256 amount) beforeDeadline {
+    require(token.transferFrom(msg.sender, this, amount));
+    if (0 == donorDonations[msg.sender]) donorCount += 1;
+    donations += amount;
+    donorDonations[msg.sender] += amount;
+  }
+
+  function answer(string _tweetUrl) beforeDeadline {
+    require(bytes(_tweetUrl).length != 0);
+    // todo check tweet more carefully, get charity id
+    tweetUrl = _tweetUrl;
+    assert(token.transfer(charities[0].addr, donations));
+  }
+
+  function revertDonation()  {
+    require(bytes(tweetUrl).length == 0);
+    require(now >= deadline);
+    require(donorDonations[msg.sender] != 0);
+    assert(token.transfer(msg.sender, donorDonations[msg.sender]));
+    donorCount -= 1;
+    donations -= donorDonations[msg.sender];
+    donorDonations[msg.sender] = 0;
+  }
+}

truffle/test/Question.js

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+/* global artifacts contract it assert web3 */
+
+const { assertError } = require('./common');
+
+const ERC20Token = artifacts.require('ERC20Token');
+const Question = artifacts.require('Question');
+
+const increaseTime = (seconds = 0) => web3.currentProvider.send({
+  jsonrpc: '2.0', method: 'evm_increaseTime', params: [seconds] }).result;
+
+// https://github.com/ethereumjs/testrpc/issues/390
+const increasedSeconds = increaseTime();
+const testBeforeNowDate = Math.floor(Date.now() / 1000) + (increasedSeconds - 5);
+const testAfterNowDate = Math.floor(Date.now() / 1000) + (increasedSeconds + 5);
+const testQuestion = 'test_question';
+const testAccount = 'test_account';
+const testAnswer = 'test_answer';
+
+contract('Question', (accounts) => {
+  it('can\'t be deployed with unset question', () =>
+    Question.new(ERC20Token.address, '', testAccount, testAfterNowDate)
+      .then(assert.fail, assertError));
+
+  it('can\'t be deployed with unset account', () =>
+    Question.new(ERC20Token.address, testQuestion, '', testAfterNowDate)
+      .then(assert.fail, assertError));
+
+  it('can\'t be deployed with deadline before current date', () =>
+    Question.new(ERC20Token.address, testQuestion, testAccount, testBeforeNowDate)
+      .then(assert.fail, assertError));
+
+  it('should be deployable', () =>
+    Question.new(ERC20Token.address, testQuestion, testAccount, testAfterNowDate)
+      .then(instance =>
+        Promise.all([
+          instance.version.call().then(c => assert.equal(c, 1)),
+          instance.getCharitiesCount.call().then(c => assert.equal(c, 4)),
+          instance.question.call().then(q => assert.equal(q, testQuestion)),
+          instance.twitterAccount.call().then(t => assert.equal(t, testAccount)),
+          instance.deadline.call().then(d => assert.equal(d, testAfterNowDate)),
+        ])));
+
+  it('can\'t increase after deadline', () =>
+    Question.new(ERC20Token.address, testQuestion, testAccount, testBeforeNowDate)
+      .then(question => question.increase(0))
+      .then(assert.fail, assertError));
+
+  const newDonatedQuestion = amount =>
+    Promise.all([
+      Question.new(ERC20Token.address, testQuestion, testAccount, testAfterNowDate),
+      ERC20Token.deployed(),
+    ])
+      .then(([question, token]) =>
+        token.approve(question.address, amount)
+          .then(() => question.increase(amount))
+          .then(() => question));
+
+  it('increase', () => {
+    const amount = 1;
+    return newDonatedQuestion(amount)
+      .then(question =>
+        Promise.all([
+          question.donorDonations.call(accounts[0]).then(d => assert.equal(d, amount)),
+          question.donorCount.call().then(c => assert.equal(c, 1)),
+          question.donations.call().then(d => assert.equal(d, amount)),
+        ]));
+  });
+
+  it('can\'t answer after deadline', () =>
+    Question.new(ERC20Token.address, testQuestion, testAccount, testBeforeNowDate)
+      .then(question => question.answer(testAnswer))
+      .then(assert.fail, assertError));
+
+  it('answer', () =>
+    newDonatedQuestion(1)
+      .then(question =>
+        question.answer(testAnswer)
+          .then(() => question.tweetUrl.call()))
+      .then(t => assert.equal(t, testAnswer)));
+
+  it('answer with transfer to charity', () => {
+    const amount = 1;
+    return Promise.all([
+      newDonatedQuestion(amount),
+      ERC20Token.deployed(),
+    ])
+      .then(([question, token]) =>
+        question.charities.call(0)
+          .then(([, charityAddress]) =>
+            token.balanceOf.call(charityAddress)
+              .then(charityBalance =>
+                question.answer(testAnswer)
+                  .then(() => token.balanceOf.call(charityAddress))
+                  .then(newCharityBalance =>
+                    assert.equal(newCharityBalance.comparedTo(charityBalance.plus(amount)), 0)))));
+  });
+
+  it('can\'t revert donation before deadline', () => {
+    const amount = 1;
+    return newDonatedQuestion(amount)
+      .then(question => question.revertDonation())
+      .then(assert.fail, assertError);
+  });
+
+  it('revert donation', () => {
+    const amount = 1;
+    return Promise.all([
+      newDonatedQuestion(amount)
+        .then((token) => {
+          increaseTime(10);
+          return token;
+        }),
+      ERC20Token.deployed(),
+    ])
+      .then(([question, token]) =>
+        token.balanceOf.call(accounts[0])
+          .then(accountBalance =>
+            question.revertDonation()
+              .then(() => token.balanceOf.call(accounts[0]))
+              .then(newAccountBalance =>
+                assert.equal(newAccountBalance.comparedTo(accountBalance.plus(amount)), 0))));
+  });
+});