Test setup helper added (#1482)

* signing prefix added

* Minor improvement

* Tests changed

* Successfully tested

* Minor improvements

* Minor improvements

* Revert "Dangling commas are now required. (#1359)"

This reverts commit a6889776f4.

* updates

* fixes #1404

* approve failing test

* suggested changes done

* ISafeERC20 removed

* conflict fixes

* fixes #1205

* minor change

* suggested changes

* reviewed changes

* final update

test/helpers/expectEvent.js

@@ -1,11 +1,8 @@
+const { should, BigNumber } = require('./setup');
+
 const SolidityEvent = require('web3/lib/web3/event.js');
 const { ethGetTransactionReceipt } = require('./web3');
 
-const BigNumber = web3.BigNumber;
-const should = require('chai')
-  .use(require('chai-bignumber')(BigNumber))
-  .should();
-
 function inLogs (logs, eventName, eventArgs = {}) {
   const event = logs.find(function (e) {
     if (e.event === eventName) {