discover-dapps/utils/testUtils.js

/*global assert, web3 */
const bs58 = require('bs58')

// This has been tested with the real Ethereum network and Testrpc.
// Copied and edited from: https://gist.github.com/xavierlepretre/d5583222fde52ddfbc58b7cfa0d2d0a9

exports.assertReverts = (contractMethodCall, maxGasAvailable) => {
  return new Promise((resolve, reject) => {
    try {
      resolve(contractMethodCall())
    } catch (error) {
      reject(error)
    }
  })
    .then(tx => {
      assert.equal(
        tx.receipt.gasUsed,
        maxGasAvailable,
        'tx successful, the max gas available was not consumed',
      )
    })
    .catch(error => {
      if (
        String(error).indexOf('invalid opcode') < 0 &&
        String(error).indexOf('out of gas') < 0
      ) {
        // Checks if the error is from TestRpc. If it is then ignore it.
        // Otherwise relay/throw the error produced by the above assertion.
        // Note that no error is thrown when using a real Ethereum network AND the assertion above is true.
        throw error
      }
    })
}

exports.listenForEvent = event =>
  new Promise((resolve, reject) => {
    event({}, (error, response) => {
      if (!error) {
        resolve(response.args)
      } else {
        reject(error)
      }
      event.stopWatching()
    })
  })

exports.eventValues = (receipt, eventName) => {
  if (receipt.events[eventName]) return receipt.events[eventName].returnValues
}

exports.addressToBytes32 = address => {
  const stringed =
    '0000000000000000000000000000000000000000000000000000000000000000' +
    address.slice(2)
  return `0x${  stringed.substring(stringed.length - 64, stringed.length)}`;
}

// OpenZeppelin's expectThrow helper -
// Source: https://github.com/OpenZeppelin/zeppelin-solidity/blob/master/test/helpers/expectThrow.js
exports.expectThrow = async promise => {
  try {
    await promise
  } catch (error) {
    // TODO: Check jump destination to destinguish between a throw
    //       and an actual invalid jump.
    const invalidOpcode = error.message.search('invalid opcode') >= 0
    // TODO: When we contract A calls contract B, and B throws, instead
    //       of an 'invalid jump', we get an 'out of gas' error. How do
    //       we distinguish this from an actual out of gas event? (The
    //       testrpc log actually show an 'invalid jump' event.)
    const outOfGas = error.message.search('out of gas') >= 0
    const revert = error.message.search('revert') >= 0
    assert(
      invalidOpcode || outOfGas || revert,
      `Expected throw, got '${  error  }' instead`,
    )
    return
  }
  assert.fail('Expected throw not received')
}

exports.assertJump = error => {
  assert(
    error.message.search('VM Exception while processing transaction: revert') >
      -1,
    'Revert should happen',
  )
}

function callbackToResolve(resolve, reject) {
  return function(error, value) {
    if (error) {
      reject(error)
    } else {
      resolve(value)
    }
  }
}

exports.promisify = func => (...args) => {
  return new Promise((resolve, reject) => {
    const callback = (err, data) => (err ? reject(err) : resolve(data))
    func.apply(this, [...args, callback])
  })
}

exports.zeroAddress = '0x0000000000000000000000000000000000000000'
exports.zeroBytes32 =
  '0x0000000000000000000000000000000000000000000000000000000000000000'
exports.timeUnits = {
  seconds: 1,
  minutes: 60,
  hours: 60 * 60,
  days: 24 * 60 * 60,
  weeks: 7 * 24 * 60 * 60,
  years: 365 * 24 * 60 * 60,
}

exports.ensureException = function(error) {
  assert(isException(error), error.toString())
}

function isException(error) {
  const strError = error.toString()
  return (
    strError.includes('invalid opcode') ||
    strError.includes('invalid JUMP') ||
    strError.includes('revert')
  )
}

const evmMethod = (method, params = []) => {
  return new Promise(function(resolve, reject) {
    const sendMethod = web3.currentProvider.sendAsync
      ? web3.currentProvider.sendAsync.bind(web3.currentProvider)
      : web3.currentProvider.send.bind(web3.currentProvider)
    sendMethod(
      {
        jsonrpc: '2.0',
        method,
        params,
        id: new Date().getSeconds(),
      },
      (error, res) => {
        if (error) {
          return reject(error)
        }
        resolve(res.result)
      },
    )
  })
}

exports.evmSnapshot = async () => {
  const result = await evmMethod('evm_snapshot')
  return web3.utils.hexToNumber(result)
}

exports.evmRevert = id => {
  const params = [id]
  return evmMethod('evm_revert', params)
}

exports.increaseTime = async amount => {
  await evmMethod('evm_increaseTime', [Number(amount)])
  await evmMethod('evm_mine')
}

exports.getBytes32FromIpfsHash = ipfsListing => {
  const decodedHash = bs58
    .decode(ipfsListing)
    .slice(2)
    .toString('hex')
  return `0x${decodedHash}`
}

exports.getIpfsHashFromBytes32 = bytes32Hex => {
  const hashHex = `1220${bytes32Hex.slice(2)}`
  const hashBytes = Buffer.from(hashHex, 'hex')
  const hashStr = bs58.encode(hashBytes)
  return hashStr
}