script.txt

What is Truffle:
Ethereum and smart contract development framework
Contains tools for:
Compiling, linking, deploying and managing contracts
Automated Testing tools
Deployment and Migration scripts
Network management for keeping track of contracts deployed on different networks
External Packages from NPM and EthPM
Console for interacting with contracts
Scripting for interacting with contracts

mkdir denvertoken
cd denvertoken
truffle unbox tutorialtoken

# run through folder structure: 
## contracts
## migrations
## src
## test
## truffle.js

code contracts/DenverToken.sol

pragma solidity ^0.4.17;

contract DenverToken {
}

npm install zeppelin-solidity

import 'zeppelin-solidity/contracts/token/ERC20/StandardToken.sol';

contract DenverToken is StandardToken, Ownable {

string public name = "DenverToken";
string public symbol = "DT";
uint8 public decimals = 2;
uint public INITIAL_SUPPLY = 20000;

function DenverToken() public {
  totalSupply_ = INITIAL_SUPPLY;
  balances[msg.sender] = INITIAL_SUPPLY;
}

code migrations/2_deploy_contracts.js

const DenverToken = artifacts.require("DenverToken");

module.exports = function(deployer) {
  deployer.deploy(DenverToken);
};

truffle compile

# Ganache

truffle migrate
truffle console
let instance = null
DenverToken.deployed().then(_instance => instance = _instance)
instance.totalSupply.call().then(result => result.toString())
instance.balanceOf.call('0x627306090abab3a6e1400e9345bc60c78a8bef57').then(result => result.toString())
instance.transfer('0xf17f52151EbEF6C7334FAD080c5704D77216b732', 1234).then(result => console.log(result.logs[0].args))
instance.balanceOf.call('0xf17f52151EbEF6C7334FAD080c5704D77216b732').then(result => result.toString())
instance.balanceOf.call('0x627306090abab3a6e1400e9345bc60c78a8bef57').then(result => result.toString())

# add ownership
Add zeppelin Ownable.sol to DenverToken
console > migrate --reset
DenverToken.deployed().then(_instance => instance = _instance)
instance.owner.call().then(result => result.toString())

DenverToken.sol

import 'zeppelin-solidity/contracts/ownership/Ownable.sol';

contract DenverToken is StandardToken, Ownable {

# now we want to add some custom functionality to our contract

console > .exit

# TESTING

code test/changeName.test.js

const DenverToken = artifacts.require('./DenverToken.sol')

contract('DenverToken', function(accounts) {
  const owner = accounts[0]
  const notOwner = accounts[1]

  let contract = null

  beforeEach( async () => {
    contract = await DenverToken.new({from:owner})
  })

  describe('.changeName', () => {
    it('it should allow the owner to change the token name', async () => {
      const newName = 'New Name'
      await contract.changeName(newName, {from:owner})
      const currentName = await contract.name.call()
      assert.equal(currentName, newName, "name did not successfully change")
    })
   })
})

truffle test

# Switch to DenverToken.sol 

function changeName(string _name) 
  public 
  onlyOwner 
  returns (bool success)
{
  name = _name;
  return true;
}

truffle test

Add a sad path test
const isEVMException = err => (
  err.toString().includes('revert')
)

...

it('it should not allow other accounts to change the token name', async () => {
  const errMsg = "A non-owner was allowed to change the name"
  const newName = 'New Name'
  const originalName = await contract.name.call()
  
  try {
    await contract.changeName(newName, {from:notOwner})
  } catch(err) {
    assert(isEVMException(err), err.toString())

    const currentName = await contract.name.call()

    assert.equal(currentName, originalName, errMsg)
    return
  }

  assert(false, errMsg)
})