Add BigNumber support to expectEvent/inLogs (#1026) (#1338)

* Add BigNumber support to expectEvent/inLogs (#1026)

* switched direct logs array check to expectEvent method in AllowanceCrowdsale.test.js

* Refactor expectEvent.inLogs function to use simple value number check

* Introduced should.be.bignumber method to compare BigNumber values

* Destructure transaction object to extract logs field

(cherry picked from commit 947de54cee)

test/helpers/expectEvent.js

@@ -1,24 +1,18 @@
-const should = require('chai').should();
+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) {
-      let matches = true;
-
       for (const [k, v] of Object.entries(eventArgs)) {
-        if (e.args[k] !== v) {
-          matches = false;
-        }
-      }
-
-      if (matches) {
-        return true;
+        contains(e.args, k, v);
       }
+      return true;
     }
   });
-
   should.exist(event);
-
   return event;
 }
 
@@ -27,6 +21,20 @@ async function inTransaction (tx, eventName, eventArgs = {}) {
   return inLogs(logs, eventName, eventArgs);
 }
 
+function contains (args, key, value) {
+  if (isBigNumber(args[key])) {
+    args[key].should.be.bignumber.equal(value);
+  } else {
+    args[key].should.be.equal(value);
+  }
+}
+
+function isBigNumber (object) {
+  return object.isBigNumber ||
+    object instanceof BigNumber ||
+    (object.constructor && object.constructor.name === 'BigNumber');
+}
+
 module.exports = {
   inLogs,
   inTransaction,