Add smart contract tests (Truffle)

smart_contract/contracts/Migrations.sol

@@ -0,0 +1,23 @@
+pragma solidity ^0.4.17;
+
+contract Migrations {
+  address public owner;
+  uint public last_completed_migration;
+
+  modifier restricted() {
+    if (msg.sender == owner) _;
+  }
+
+  constructor() public {
+    owner = msg.sender;
+  }
+
+  function setCompleted(uint completed) public restricted {
+    last_completed_migration = completed;
+  }
+
+  function upgrade(address new_address) public restricted {
+    Migrations upgraded = Migrations(new_address);
+    upgraded.setCompleted(last_completed_migration);
+  }
+}

smart_contract/contracts/test/DummyExchange.sol

@@ -0,0 +1,41 @@
+pragma solidity ^0.4.24;
+
+// a dummy exchange implementation to test deposited balances
+
+
+contract SafeMath {
+  function safeAdd(uint256 a, uint256 b) internal pure returns (uint256 c) {
+    c = a + b;
+    require(c >= a);
+    return c;
+  }
+}
+
+contract Token {
+  function balanceOf(address _owner) external view returns (uint256 balance);
+  function transferFrom(address _from, address _to, uint256 _value) public returns (bool success);
+}
+
+contract DummyExchange is SafeMath{
+
+    mapping (address => mapping (address => uint)) public balances;
+
+    constructor() public {}
+
+    function deposit() external payable {
+      balances[0][msg.sender] = safeAdd(balances[0][msg.sender], msg.value);
+    }
+
+    // requires token.approve
+    function depositToken(address token, uint amount) external {
+      require(token != address(0x0));
+
+      require(Token(token).transferFrom(msg.sender, address(this), amount));
+      balances[token][msg.sender] = safeAdd(balances[token][msg.sender], amount);
+    }
+
+    function balanceOf(address token, address user) external view returns (uint) {
+      return balances[token][user];
+    }
+}
+

smart_contract/contracts/test/ERC20.sol

@@ -0,0 +1,170 @@
+pragma solidity ^0.4.24;
+
+// erc20 implementations for testing
+// needs some SafeMath for actual usage
+
+// deliberately missing allowance() and balanceOf()
+contract IncompleteERC20 {
+    uint256 constant internal MAX_UINT256 = 2**256 - 1;
+    mapping (address => uint256) public balances;
+    mapping (address => mapping (address => uint256)) public allowed;
+
+    uint256 public totalSupply;
+
+    string public name;      
+    uint8 public decimals;  
+    string public symbol;
+
+	event Transfer(address indexed _from, address indexed _to, uint256 _value);
+    event Approval(address indexed _owner, address indexed _spender, uint256 _value);
+
+    constructor (
+        uint256 _initialAmount,
+        string _tokenName,
+        uint8 _decimalUnits,
+        string _tokenSymbol
+    ) public {
+        balances[msg.sender] = _initialAmount;
+        totalSupply = _initialAmount;
+        name = _tokenName;
+        decimals = _decimalUnits;
+        symbol = _tokenSymbol;
+    }
+
+    function transfer(address _to, uint256 _value) public returns (bool success) {
+        require(balances[msg.sender] >= _value);
+        balances[msg.sender] -= _value;
+        balances[_to] += _value;
+        emit Transfer(msg.sender, _to, _value);
+        return true;
+    }
+
+    function transferFrom(address _from, address _to, uint256 _value) public returns (bool success) {
+        uint256 allowance = allowed[_from][msg.sender];
+        require(balances[_from] >= _value && allowance >= _value);
+        balances[_to] += _value;
+        balances[_from] -= _value;
+        if (allowance < MAX_UINT256) {
+            allowed[_from][msg.sender] -= _value;
+        }
+        emit Transfer(_from, _to, _value);
+        return true;
+    }
+
+    /*
+    function balanceOf(address _owner) public view returns (uint256 balance) {
+        return balances[_owner];
+    }
+    */
+
+    function approve(address _spender, uint256 _value) public returns (bool success) {
+        allowed[msg.sender][_spender] = _value;
+        emit Approval(msg.sender, _spender, _value); //solhint-disable-line indent, no-unused-vars
+        return true;
+    }
+
+    /* 
+    function allowance(address _owner, address _spender) public view returns (uint256 remaining) {
+        return allowed[_owner][_spender];
+    } 
+    */
+}
+
+//make it a valid ERC20
+contract ERC20 is IncompleteERC20 {
+
+    constructor (
+        uint256 _initialAmount,
+        string _tokenName,
+        uint8 _decimalUnits,
+        string _tokenSymbol
+    )  IncompleteERC20(_initialAmount, _tokenName, _decimalUnits, _tokenSymbol) 
+    public { }
+
+    function allowance(address _owner, address _spender) public view returns (uint256 remaining) {
+        return allowed[_owner][_spender];
+    }
+
+    function balanceOf(address _owner) public view returns (uint256 balance) {
+        return balances[_owner];
+    }
+}
+
+// ERC20 with failing functions
+contract BadERC20 is IncompleteERC20 {
+
+    constructor (
+        uint256 _initialAmount,
+        string _tokenName,
+        uint8 _decimalUnits,
+        string _tokenSymbol
+    )  IncompleteERC20(_initialAmount, _tokenName, _decimalUnits, _tokenSymbol) 
+    public { }
+
+    function allowance(address _owner, address _spender) public view returns (uint256 remaining) {
+        require(false);
+        return 0;
+    }
+
+    function balanceOf(address _owner) public view returns (uint256 balance) {
+        require(false);
+        return 0;
+    }
+}
+
+//erc20 contract that can selfdestruct
+contract KillERC20 is ERC20 {
+
+    constructor (
+        uint256 _initialAmount,
+        string _tokenName,
+        uint8 _decimalUnits,
+        string _tokenSymbol
+    )  ERC20(_initialAmount, _tokenName, _decimalUnits, _tokenSymbol) 
+    public { }
+
+    function kill() external {
+		selfdestruct(msg.sender);
+	}
+}
+
+// ERC20 with public variables instead of normal functions
+contract AltERC20 is IncompleteERC20 {
+
+    mapping (address => uint256) public balanceOf;
+    mapping (address => mapping (address => uint256)) public allowance;
+
+    constructor (
+        uint256 _initialAmount,
+        string _tokenName,
+        uint8 _decimalUnits,
+        string _tokenSymbol
+    )  IncompleteERC20(_initialAmount, _tokenName, _decimalUnits, _tokenSymbol) 
+    public { }
+
+    function transfer(address _to, uint256 _value) public returns (bool success) {
+        require(balanceOf[msg.sender] >= _value);
+        balanceOf[msg.sender] -= _value;
+        balanceOf[_to] += _value;
+        emit Transfer(msg.sender, _to, _value);
+        return true;
+    }
+
+    function transferFrom(address _from, address _to, uint256 _value) public returns (bool success) {
+        uint256 allowance2 = allowance[_from][msg.sender];
+        require(balances[_from] >= _value && allowance2 >= _value);
+        balances[_to] += _value;
+        balances[_from] -= _value;
+        if (allowance2 < MAX_UINT256) {
+            allowance[_from][msg.sender] -= _value;
+        }
+        emit Transfer(_from, _to, _value);
+        return true;
+    }
+
+    function approve(address _spender, uint256 _value) public returns (bool success) {
+        allowance[msg.sender][_spender] = _value;
+        emit Approval(msg.sender, _spender, _value);
+        return true;
+    }
+}

smart_contract/migrations/1_initial_migration.js

@@ -0,0 +1,5 @@
+var Migrations = artifacts.require("./Migrations.sol");
+
+module.exports = function(deployer) {
+  deployer.deploy(Migrations);
+};

smart_contract/migrations/2_contract_migration.js

@@ -0,0 +1,5 @@
+const DeltaBalances = artifacts.require("DeltaBalances");
+
+module.exports = function(deployer) {
+	deployer.deploy(DeltaBalances); 
+};

smart_contract/readme.md

@@ -0,0 +1,24 @@
+Contract `deltabalances.sol` is located in `./test`
+Deployed on mainnet at [0x40a38911e470fc088beeb1a9480c2d69c847bcec](https://etherscan.io/address/0x40a38911e470fc088beeb1a9480c2d69c847bcec)
+
+
+# Testing with Truffle
+
+**Install**
+Install the following to be able to run the tests
+`npm install -g truffle` (Ethereum Development suite)
+`npm install -g ganache-cli` (Virtual Ethereum node)
+
+
+**Setup tests**
+Before testing, start ganache (port 7545, as defined in truffle-config.js)
+`ganache-cli -p 7545`
+
+Build and deploy the virtual contracts
+`truffle migrate`
+
+**Run all tests**
+`truffle test`
+**Run a specific test file**
+`truffle test ./test/filename.js`
+