contracts/Contribution.sol

@@ -2,10 +2,6 @@ pragma solidity ^0.8.0;
 
 import "@openzeppelin/contracts-upgradeable/proxy/utils/Initializable.sol";
 
-interface IToken {
-  function mintFor(address contributorAccount, uint256 amount, uint32 contributionId) external;
-}
-
 interface ContributorInterface {
   function getContributorAddressById(uint32 contributorId) external view returns (address);
   function getContributorIdByAddress(address contributorAccount) external view returns (uint32);
@@ -16,12 +12,10 @@ interface ContributorInterface {
 
 contract Contribution is Initializable {
   ContributorInterface public contributorContract;
-  IToken public tokenContract;
 
   struct ContributionData {
     uint32 contributorId;
     uint32 amount;
-    bool claimed;
     bytes32 hashDigest;
     uint8 hashFunction;
     uint8 hashSize;
@@ -52,7 +46,6 @@ contract Contribution is Initializable {
   bool public migrationDone;
 
   event ContributionAdded(uint32 id, uint32 indexed contributorId, uint32 amount);
-  event ContributionClaimed(uint32 id, uint32 indexed contributorId, uint32 amount);
   event ContributionVetoed(uint32 id, address vetoedByAccount);
 
   modifier onlyCore {
@@ -75,11 +68,6 @@ contract Contribution is Initializable {
     migrationDone = true;
   }
 
-  function setTokenContract(address token) public {
-    require(address(tokenContract) == address(0) || contributorContract.addressIsCore(msg.sender), "Core only");
-    tokenContract = IToken(token);
-  }
-
   function setContributorContract(address contributor) public {
     require(address(contributorContract) == address(0) || contributorContract.addressIsCore(msg.sender), "Core only");
     contributorContract = ContributorInterface(contributor);
@@ -151,14 +139,13 @@ contract Contribution is Initializable {
     }
   }
 
-  function getContribution(uint32 contributionId) public view returns (uint32 id, uint32 contributorId, uint32 amount, bool claimed, bytes32 hashDigest, uint8 hashFunction, uint8 hashSize, uint256 confirmedAtBlock, bool exists, bool vetoed) {
+  function getContribution(uint32 contributionId) public view returns (uint32 id, uint32 contributorId, uint32 amount, bytes32 hashDigest, uint8 hashFunction, uint8 hashSize, uint256 confirmedAtBlock, bool exists, bool vetoed) {
     id = contributionId;
     ContributionData storage c = contributions[id];
     return (
       id,
       c.contributorId,
       c.amount,
-      c.claimed,
       c.hashDigest,
       c.hashFunction,
       c.hashSize,
@@ -178,7 +165,6 @@ contract Contribution is Initializable {
     ContributionData storage c = contributions[contributionId];
     c.exists = true;
     c.amount = amount;
-    c.claimed = false;
     c.contributorId = contributorId;
     c.hashDigest = hashDigest;
     c.hashFunction = hashFunction;
@@ -203,29 +189,13 @@ contract Contribution is Initializable {
   function veto(uint32 contributionId) public onlyCore {
     ContributionData storage c = contributions[contributionId];
     require(c.exists, 'NOT_FOUND');
-    require(!c.claimed, 'ALREADY_CLAIMED');
     require(block.number < c.confirmedAtBlock, 'VETO_PERIOD_ENDED');
     c.vetoed = true;
 
     emit ContributionVetoed(contributionId, msg.sender);
   }
 
-  function claim(uint32 contributionId) public {
-    ContributionData storage c = contributions[contributionId];
-    require(c.exists, 'NOT_FOUND');
-    require(!c.claimed, 'ALREADY_CLAIMED');
-    require(!c.vetoed, 'VETOED');
-    require(block.number >= c.confirmedAtBlock, 'NOT_CLAIMABLE');
-
-    c.claimed = true;
-    address contributorAccount = getContributorAddressById(c.contributorId);
-    uint256 amount = uint256(c.amount);
-    tokenContract.mintFor(contributorAccount, amount, contributionId);
-    emit ContributionClaimed(contributionId, c.contributorId, c.amount);
-  }
-
   function exists(uint32 contributionId) public view returns (bool) {
     return contributions[contributionId].exists;
   }
-
 }

contracts/Contributor.sol

@@ -2,7 +2,8 @@ pragma solidity ^0.8.0;
 
 import "@openzeppelin/contracts-upgradeable/proxy/utils/Initializable.sol";
 
-interface ITokenBalance {
+interface IToken {
+  function mintFor(address contributorAccount, uint256 amount) external;
   function balanceOf(address contributorAccount) external view returns (uint256);
 }
 interface IContributionBalance {
@@ -11,9 +12,9 @@ interface IContributionBalance {
 }
 
 contract Contributor is Initializable {
-  address deployer;
+  address public deployer;
   IContributionBalance public contributionContract;
-  ITokenBalance public tokenContract;
+  IToken public tokenContract;
 
   struct Contributor {
     address account;
@@ -21,6 +22,7 @@ contract Contributor is Initializable {
     uint8 hashFunction;
     uint8 hashSize;
     bool exists;
+    uint32 kreditsWithdrawn;
   }
 
   mapping (address => uint32) public contributorIds;
@@ -36,6 +38,11 @@ contract Contributor is Initializable {
     _;
   }
 
+  modifier onlyContributors {
+    require(addressExists(msg.sender) && contributionContract.balanceOf(msg.sender) > 0, "Contributors only");
+    _;
+  }
+
   function initialize() public initializer {
     deployer = msg.sender;
   }
@@ -47,7 +54,7 @@ contract Contributor is Initializable {
 
   function setTokenContract(address token) public onlyCore {
     require(address(tokenContract) == address(0) || addressIsCore(msg.sender), "Core only");
-    tokenContract = ITokenBalance(token);
+    tokenContract = IToken(token);
   }
 
   function coreContributorsCount() public view returns (uint32) {
@@ -81,7 +88,7 @@ contract Contributor is Initializable {
   }
 
   function addContributor(address account, bytes32 hashDigest, uint8 hashFunction, uint8 hashSize) public onlyCore {
-    require(!addressExists(account));
+    require(!addressExists(account), "Address already in use");
     uint32 _id = contributorsCount + 1;
     assert(!contributors[_id].exists); // this can not be acually
     Contributor storage c = contributors[_id];
@@ -90,6 +97,7 @@ contract Contributor is Initializable {
     c.hashFunction = hashFunction;
     c.hashSize = hashSize;
     c.account = account;
+    c.kreditsWithdrawn = 0;
     contributorIds[account] = _id;
 
     contributorsCount += 1;
@@ -132,7 +140,7 @@ contract Contributor is Initializable {
     return contributors[id];
   }
 
-  function getContributorById(uint32 _id) public view returns (uint32 id, address account, bytes32 hashDigest, uint8 hashFunction, uint8 hashSize, bool isCore, uint256 balance, uint32 totalKreditsEarned, uint256 contributionsCount, bool exists ) {
+  function getContributorById(uint32 _id) view public returns (uint32 id, address account, bytes32 hashDigest, uint8 hashFunction, uint8 hashSize, bool isCore, uint256 balance, uint32 totalKreditsEarned, uint256 contributionsCount, bool exists, uint256 kreditsWithdrawn) {
     id = _id;
     Contributor storage c = contributors[_id];
     account = c.account;
@@ -144,6 +152,19 @@ contract Contributor is Initializable {
     totalKreditsEarned = contributionContract.totalKreditsEarnedByContributor(_id, true);
     contributionsCount = contributionContract.balanceOf(c.account);
     exists = c.exists;
+    kreditsWithdrawn = c.kreditsWithdrawn;
   }
 
+  function withdraw() public onlyContributors {
+    uint32 id = getContributorIdByAddress(msg.sender);
+    Contributor storage c = contributors[id];
+
+    // TODO check if we need a failsafe for unconfirmed or malicious txs
+    uint32 confirmedKredits = contributionContract.totalKreditsEarnedByContributor(id, true);
+    uint32 amountWithdrawable = confirmedKredits - c.kreditsWithdrawn;
+    require (amountWithdrawable > 0, "No kredits available");
+
+    c.kreditsWithdrawn += amountWithdrawable;
+    tokenContract.mintFor(msg.sender, amountWithdrawable);
+  }
 }

contracts/Token.sol

@@ -7,38 +7,32 @@ interface ContributorInterface {
   function getContributorAddressById(uint32 contributorId) external view returns (address);
   function getContributorIdByAddress(address contributorAccount) external view returns (uint32);
   function addressIsCore(address sender) external view returns (bool);
-  // TODO Maybe use for validation
-  // function exists(uint32 contributorId) public view returns (bool);
 }
 
 contract Token is Initializable, ERC20Upgradeable {
   ContributorInterface public contributorContract;
   using SafeMathUpgradeable for uint256;
 
-  address public contributionContract;
+  address public contributorContractAddress;
 
-  event LogMint(address indexed recipient, uint256 amount, uint32 contributionId);
+  event KreditsMinted(address indexed recipient, uint256 amount);
 
   function initialize() public virtual initializer {
     __ERC20_init('Kredits', 'KS');
   }
 
-  function setContributionContract(address contribution) public {
-    require(address(contributionContract) == address(0) || contributorContract.addressIsCore(msg.sender), "Core only");
-    contributionContract = contribution;
-  }
   function setContributorContract(address contributor) public {
     require(address(contributorContract) == address(0) || contributorContract.addressIsCore(msg.sender), "Core only");
     contributorContract = ContributorInterface(contributor);
+    contributorContractAddress = contributor;
   }
 
-  function mintFor(address contributorAccount, uint256 amount, uint32 contributionId) public {
+  function mintFor(address contributorAccount, uint256 amount) public {
-    require(contributionContract == msg.sender, "Only Contribution");
+    require(contributorContractAddress == msg.sender, "Only Contributor");
     require(amount > 0, "INVALID_AMOUNT");
 
     uint256 amountInWei = amount.mul(1 ether);
     _mint(contributorAccount, amountInWei);
-    emit LogMint(contributorAccount, amount, contributionId);
+    emit KreditsMinted(contributorAccount, amount);
   }
-
 }

lib/abis/Token.json

@@ -1 +1 @@
-[{"anonymous":false,"inputs":[{"indexed":true,"internalType":"address","name":"owner","type":"address"},{"indexed":true,"internalType":"address","name":"spender","type":"address"},{"indexed":false,"internalType":"uint256","name":"value","type":"uint256"}],"name":"Approval","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"address","name":"recipient","type":"address"},{"indexed":false,"internalType":"uint256","name":"amount","type":"uint256"},{"indexed":false,"internalType":"uint32","name":"contributionId","type":"uint32"}],"name":"LogMint","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"address","name":"from","type":"address"},{"indexed":true,"internalType":"address","name":"to","type":"address"},{"indexed":false,"internalType":"uint256","name":"value","type":"uint256"}],"name":"Transfer","type":"event"},{"inputs":[{"internalType":"address","name":"owner","type":"address"},{"internalType":"address","name":"spender","type":"address"}],"name":"allowance","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"spender","type":"address"},{"internalType":"uint256","name":"amount","type":"uint256"}],"name":"approve","outputs":[{"internalType":"bool","name":"","type":"bool"}],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"address","name":"account","type":"address"}],"name":"balanceOf","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"contributionContract","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"contributorContract","outputs":[{"internalType":"contract ContributorInterface","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"decimals","outputs":[{"internalType":"uint8","name":"","type":"uint8"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"spender","type":"address"},{"internalType":"uint256","name":"subtractedValue","type":"uint256"}],"name":"decreaseAllowance","outputs":[{"internalType":"bool","name":"","type":"bool"}],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"address","name":"spender","type":"address"},{"internalType":"uint256","name":"addedValue","type":"uint256"}],"name":"increaseAllowance","outputs":[{"internalType":"bool","name":"","type":"bool"}],"stateMutability":"nonpayable","type":"function"},{"inputs":[],"name":"initialize","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"address","name":"contributorAccount","type":"address"},{"internalType":"uint256","name":"amount","type":"uint256"},{"internalType":"uint32","name":"contributionId","type":"uint32"}],"name":"mintFor","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[],"name":"name","outputs":[{"internalType":"string","name":"","type":"string"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"contribution","type":"address"}],"name":"setContributionContract","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"address","name":"contributor","type":"address"}],"name":"setContributorContract","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[],"name":"symbol","outputs":[{"internalType":"string","name":"","type":"string"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"totalSupply","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"to","type":"address"},{"internalType":"uint256","name":"amount","type":"uint256"}],"name":"transfer","outputs":[{"internalType":"bool","name":"","type":"bool"}],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"address","name":"from","type":"address"},{"internalType":"address","name":"to","type":"address"},{"internalType":"uint256","name":"amount","type":"uint256"}],"name":"transferFrom","outputs":[{"internalType":"bool","name":"","type":"bool"}],"stateMutability":"nonpayable","type":"function"}]
+[{"anonymous":false,"inputs":[{"indexed":true,"internalType":"address","name":"owner","type":"address"},{"indexed":true,"internalType":"address","name":"spender","type":"address"},{"indexed":false,"internalType":"uint256","name":"value","type":"uint256"}],"name":"Approval","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"address","name":"recipient","type":"address"},{"indexed":false,"internalType":"uint256","name":"amount","type":"uint256"}],"name":"KreditsMinted","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"address","name":"from","type":"address"},{"indexed":true,"internalType":"address","name":"to","type":"address"},{"indexed":false,"internalType":"uint256","name":"value","type":"uint256"}],"name":"Transfer","type":"event"},{"inputs":[{"internalType":"address","name":"owner","type":"address"},{"internalType":"address","name":"spender","type":"address"}],"name":"allowance","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"spender","type":"address"},{"internalType":"uint256","name":"amount","type":"uint256"}],"name":"approve","outputs":[{"internalType":"bool","name":"","type":"bool"}],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"address","name":"account","type":"address"}],"name":"balanceOf","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"contributorContract","outputs":[{"internalType":"contract ContributorInterface","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"contributorContractAddress","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"decimals","outputs":[{"internalType":"uint8","name":"","type":"uint8"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"spender","type":"address"},{"internalType":"uint256","name":"subtractedValue","type":"uint256"}],"name":"decreaseAllowance","outputs":[{"internalType":"bool","name":"","type":"bool"}],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"address","name":"spender","type":"address"},{"internalType":"uint256","name":"addedValue","type":"uint256"}],"name":"increaseAllowance","outputs":[{"internalType":"bool","name":"","type":"bool"}],"stateMutability":"nonpayable","type":"function"},{"inputs":[],"name":"initialize","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"address","name":"contributorAccount","type":"address"},{"internalType":"uint256","name":"amount","type":"uint256"}],"name":"mintFor","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[],"name":"name","outputs":[{"internalType":"string","name":"","type":"string"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"contributor","type":"address"}],"name":"setContributorContract","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[],"name":"symbol","outputs":[{"internalType":"string","name":"","type":"string"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"totalSupply","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"to","type":"address"},{"internalType":"uint256","name":"amount","type":"uint256"}],"name":"transfer","outputs":[{"internalType":"bool","name":"","type":"bool"}],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"address","name":"from","type":"address"},{"internalType":"address","name":"to","type":"address"},{"internalType":"uint256","name":"amount","type":"uint256"}],"name":"transferFrom","outputs":[{"internalType":"bool","name":"","type":"bool"}],"stateMutability":"nonpayable","type":"function"}]

scripts/create-proxy.js

@@ -57,16 +57,6 @@ async function main() {
       return res.wait();
     }).catch(handleError);
 
-
-  console.log('Calling Contribution#setTokenContract')
-  await contracts.Contribution.functions
-    .setTokenContract(contracts.Token.address)
-    .then(res => {
-      console.log(`...transaction published: ${res.hash}`);
-      return res.wait();
-    }).catch(handleError);
-
-
   console.log('Calling Contribution#setContributorContract')
   await contracts.Contribution.functions
     .setContributorContract(contracts.Contributor.address)
@@ -75,14 +65,6 @@ async function main() {
       return res.wait();
     }).catch(handleError);
 
-  console.log('Calling Token#setContributionContract')
-  await contracts.Token.functions
-    .setContributionContract(contracts.Contribution.address)
-    .then(res => {
-      console.log(`...transaction published: ${res.hash}`);
-      return res.wait();
-    }).catch(handleError);
-
   console.log('Calling Token#setContributorContract')
   await contracts.Token.functions
     .setContributorContract(contracts.Contributor.address)

scripts/list-contributions.js

@@ -12,7 +12,7 @@ async function main() {
   console.log(`Using Contribution at: ${kredits.Contribution.contract.address}`);
 
   const table = new Table({
-    head: ['ID', 'Contributor ID', 'Description', 'Amount', 'Confirmed?', 'Vetoed?', 'Claimed?', 'IPFS']
+    head: ['ID', 'Contributor ID', 'Description', 'Amount', 'Confirmed?', 'Vetoed?', 'IPFS']
   })
 
   try {
@@ -31,7 +31,6 @@ async function main() {
         c.amount.toString(),
         `${confirmed} (${c.confirmedAtBlock})`,
         c.vetoed,
-        c.claimed,
         c.ipfsHash
       ])
     });

test/contracts/Contribution.js

@@ -128,7 +128,7 @@ describe("Contribution contract", async function () {
       before(async function () {
         const contributionFactory = await ethers.getContractFactory("Contribution");
         Contribution = await upgrades.deployProxy(contributionFactory, [40321]);
-        await Contribution.setContributorContract(Contributor.address).then(res => res.wait())
+        await Contribution.setContributorContract(Contributor.address);
       });
 
       it("allows to add a contribution with custom confirmedAtBlock", async function () {

test/contracts/Contributor.js

@@ -1,30 +1,106 @@
 const { expect } = require("chai");
 const { ethers, upgrades } = require("hardhat");
-// const { anyValue } = require("@nomicfoundation/hardhat-chai-matchers/withArgs");
 let owner, addr1, addr2, addr3, addr4, addr5, addr6, addr7;
-let Contribution, Contributor;
+let Contribution, Contributor, Token;
 
 describe("Contributor contract", async function () {
   before(async function () {
     [owner, addr1, addr2, addr3, addr4, addr5, addr6, addr7] = await ethers.getSigners();
-    // let accounts = [owner, addr1, addr2, addr3, addr4, addr5, addr6, addr7];
+
-    // const contributorFactory = await ethers.getContractFactory("Contributor");
+    const contributorFactory = await ethers.getContractFactory("Contributor");
-    // Contributor = await upgrades.deployProxy(contributorFactory);
+    Contributor = await upgrades.deployProxy(contributorFactory);
-    // for (const account of accounts) {
+    const contributionFactory = await ethers.getContractFactory("Contribution");
-    //   await Contributor.addContributor(account.address, "0x99b8afd7b266e19990924a8be9099e81054b70c36b20937228a77a5cf75723b8", 18, 32);
+    Contribution = await upgrades.deployProxy(contributionFactory, [40321]);
-    // }
+    const tokenFactory = await ethers.getContractFactory("Token");
+    Token = await upgrades.deployProxy(tokenFactory);
+
+    await Contributor.setTokenContract(Token.address);
+    await Contributor.setContributionContract(Contribution.address);
+    await Contribution.setContributorContract(Contributor.address);
+    await Token.setContributorContract(Contributor.address);
+
+    let accounts = [owner, addr1, addr2, addr3, addr4, addr5, addr6, addr7];
+    for (const account of accounts) {
+      await Contributor.addContributor(account.address, "0x99b8afd7b266e19990924a8be9099e81054b70c36b20937228a77a5cf75723b8", 18, 32);
+    }
   });
 
   describe("initialize()", function () {
-    before(async function () {
-      // const [owner] = await ethers.getSigners();
-      const contributorFactory = await ethers.getContractFactory("Contributor");
-      Contributor = await upgrades.deployProxy(contributorFactory);
-    });
-
     it("sets the deployer address", async function () {
       expect(await Contributor.deployer()).to.equal(owner.address);
       expect(await Contributor.deployer()).to.not.equal(addr1.address);
     });
   });
+
+  describe("add()", function () {
+    it("does not allow random accounts to create a contributor profile", async function () {
+      await expect(Contributor.connect(addr7).addContributor(
+        "0x608FD4b95116Ea616990Aaeb1d4f1ce07612f261",
+        "0x1d9de6de5c72eedca6d7a5e8a9159e2f5fe676506aece3000acefcc821723429",
+        18, 32
+      )).to.be.revertedWith("Core only");
+      expect(await Contributor.contributorsCount()).to.equal(8);
+    });
+
+    it("allows core contributors to create a contributor profile", async function () {
+      await Contributor.connect(addr1).addContributor(
+        "0x608FD4b95116Ea616990Aaeb1d4f1ce07612f261",
+        "0x1d9de6de5c72eedca6d7a5e8a9159e2f5fe676506aece3000acefcc821723429",
+        18, 32
+      );
+      expect(await Contributor.contributorsCount()).to.equal(9);
+      const c = await Contributor.getContributorById(9);
+      expect(c['account']).to.equal("0x608FD4b95116Ea616990Aaeb1d4f1ce07612f261");
+      expect(c['kreditsWithdrawn']).to.equal(0);
+    });
+
+    it("does not allow to create accounts with an existing address", async function () {
+      await expect(Contributor.connect(addr1).addContributor(
+        "0x608FD4b95116Ea616990Aaeb1d4f1ce07612f261",
+        "0x1d9de6de5c72eedca6d7a5e8a9159e2f5fe676506aece3000acefcc821723429",
+        18, 32
+      )).to.be.revertedWith("Address already in use");
+      expect(await Contributor.contributorsCount()).to.equal(9);
+    });
+
+    it("emits a ContributorAdded event", async function () {
+      await expect(Contributor.connect(addr1).addContributor(
+        "0x765E88b4F9a59C3a3b300C6eFF9E6E9fDDf9FbD9",
+        "0xcfbeeadc244dfdc55bbad50d431871439df067970db84c73023956c96a6f5df2",
+        18, 32
+      )).to.emit(Contributor, "ContributorAdded").withArgs(10, "0x765E88b4F9a59C3a3b300C6eFF9E6E9fDDf9FbD9");
+    });
+  });
+
+  describe("withdraw()", function () {
+    before(async function () {
+      // Add some pre-confirmed contributions (confirmedAtBlock 1)
+      await Contribution.add(
+        1500, 2, "0xe794f010e617449719c64076546254129f63a6d16cf200031afa646aeb35777f",
+        18, 32, 1, false
+      );
+      await Contribution.add(
+        5000, 2, "0xe794f010e617449719c64076546254129f63a6d16cf200031afa646aeb35777f",
+        18, 32, 1, false
+      );
+      await Contribution.finishMigration();
+    });
+
+    it("requires the transaction sender to be a contributor", async function () {
+      await expect(Contributor.withdraw()).to.be.revertedWith("Contributors only");
+    });
+
+    it("executes a withdrawal of all available ERC20 kredits", async function () {
+      let c = await Contributor.getContributorById(2);
+      expect(c['balance']).to.equal(0);
+      await Contributor.connect(addr1).withdraw();
+      c = await Contributor.getContributorById(2);
+      expect(c['balance'].toString()).to.equal("6500000000000000000000");
+      expect(c['kreditsWithdrawn']).to.equal(6500);
+    });
+
+    it("requires the withdrawable amount to be larger than 0", async function () {
+      await expect(Contributor.connect(addr1).withdraw()).to.be.revertedWith("No kredits available");
+    });
+  });
 });