Fix randomHex (#3085)

* randomHex fixed

* Add utils.randomHex unit test

CHANGELOG.md

@@ -56,6 +56,7 @@ Released with 1.0.0-beta.37 code base.
 
 ### Fixed
 
+- Fix randomHex returning inconsistent string lengths (#1490)
 - Fix make isBN minification safe (#1777)
 - Fix incorrect references to BigNumber in utils.fromWei and utils.toWei error messages (#2468)
 - Fix error incorrectly thrown when receipt.status is `null` (#2183)

packages/web3-utils/package.json

@@ -13,7 +13,7 @@
         "eth-lib": "0.2.7",
         "ethjs-unit": "0.1.6",
         "number-to-bn": "1.7.0",
-        "randomhex": "0.1.5",
+        "randombytes": "^2.1.0",
         "underscore": "1.9.1",
         "utf8": "3.0.0"
     }

packages/web3-utils/src/index.js

@@ -26,7 +26,7 @@ var _ = require('underscore');
 var ethjsUnit = require('ethjs-unit');
 var utils = require('./utils.js');
 var soliditySha3 = require('./soliditySha3.js');
-var randomHex = require('randomhex');
+var randombytes = require('randombytes');
 
 
 
@@ -145,6 +145,16 @@ var _flattenTypes = function(includeTuple, puts)
 };
 
 
+/**
+ * Returns a random hex string by the given bytes size
+ *
+ * @param {Number} size
+ * @returns {string}
+ */
+var randomHex = function(size) {
+    return '0x' + randombytes(size).toString('hex');
+};
+
 /**
  * Should be called to get ascii from it's hex representation
  *

test/utils.randomHex.js

@@ -0,0 +1,25 @@
+var chai = require('chai');
+var utils = require('../packages/web3-utils');
+
+var assert = chai.assert;
+
+// Expect 2 chars per bytes plus `0x` prefix
+var tests = [
+    { value:  0, expected: { prefix: '0x', type: 'string', length: 2 }},
+    { value: 15, expected: { prefix: '0x', type: 'string', length: 32 }},
+    { value: 16, expected: { prefix: '0x', type: 'string', length: 34 }}
+];
+
+describe('lib/utils/utils', function () {
+    describe('randomHex', function () {
+        tests.forEach(function (test) {
+            it('should turn ' + test.value + ' to ' + test.expected, function () {
+                var result = utils.randomHex(test.value);
+
+                assert.strictEqual(typeof result, test.expected.type);
+                assert.strictEqual(result.slice(0,2), test.expected.prefix);
+                assert.strictEqual(result.length, test.expected.length);
+            });
+        });
+    });
+});