text: //This function is from zepplin-solidity.
  //Node doesn't support ES2015 so this function needs to be isolated
  //because the source file uses an import statement.
  
  // Increases testrpc time by the passed duration in seconds
  module.exports = function (duration) {
    const id = Date.now()
  
    return new Promise((resolve, reject) => {
      web3.currentProvider.sendAsync({
        jsonrpc: '2.0',
        method: 'evm_increaseTime',
        params: [duration],
        id: id,
      }, err1 => {
        if (err1) return reject(err1)
  
        web3.currentProvider.sendAsync({
          jsonrpc: '2.0',
          method: 'evm_mine',
          id: id+1,
        }, (err2, res) => {
          return err2 ? reject(err2) : resolve(res)
        })
      })
    })
  }
  