feat: manually fix linting errors across tests

test/helpers/hashMessage.js

@@ -2,7 +2,7 @@ import utils from 'ethereumjs-util';
 
 // Hash and add same prefix to the hash that testrpc use.
 module.exports = function (message) {
-  const messageHex = new Buffer(utils.sha3(message).toString('hex'), 'hex');
+  const messageHex = Buffer.from(utils.sha3(message).toString('hex'), 'hex');
   const prefix = utils.toBuffer('\u0019Ethereum Signed Message:\n' + messageHex.length.toString());
   return utils.bufferToHex(utils.sha3(Buffer.concat([prefix, messageHex])));
 };

test/helpers/merkleTree.js

@@ -15,7 +15,7 @@ export default class MerkleTree {
   }
 
   getLayers (elements) {
-    if (elements.length == 0) {
+    if (elements.length === 0) {
       return [['']];
     }
 

test/helpers/toPromise.js

@@ -1,4 +1,4 @@
 export default func =>
   (...args) =>
-    new Promise((accept, reject) =>
-      func(...args, (error, data) => error ? reject(error) : accept(data)));
+    new Promise((resolve, reject) =>
+      func(...args, (error, data) => error ? reject(error) : resolve(data)));