Update the random number package so seeding can be implemented withou…

…t seeding numbers forever. Implement seeding on the following functions:

* faker.random.number
* faker.random.array_element
* faker.commerce.productName

Added tests for seeding data and tests for array_element

lib/commerce.js

@@ -23,10 +23,16 @@ var commerce = {
         return categories[0];
     },
 
-    productName: function() {
-        return faker.commerce.productAdjective() + " " +
-                faker.commerce.productMaterial() + " " +
-                faker.commerce.product();
+    productName: function(options) {
+        options = options || {};
+
+        if (typeof options.seed === 'undefined') {
+            options.seed = null;
+        }
+
+        return faker.commerce.productAdjective(options) + " " +
+                faker.commerce.productMaterial(options) + " " +
+                faker.commerce.product(options);
     },
 
     price: function(min, max, dec, symbol) {
@@ -62,16 +68,16 @@ var commerce = {
         return [commaSeparated, categories[categories.length - 1]].join(separator);
     },
 
-    productAdjective: function() {
-        return faker.random.array_element(faker.definitions.commerce.product_name.adjective);
+    productAdjective: function(options) {
+        return faker.random.array_element(faker.definitions.commerce.product_name.adjective, options);
     },
 
-    productMaterial: function() {
-        return faker.random.array_element(faker.definitions.commerce.product_name.material);
+    productMaterial: function(options) {
+        return faker.random.array_element(faker.definitions.commerce.product_name.material, options);
     },
 
-    product: function() {
-        return faker.random.array_element(faker.definitions.commerce.product_name.product);
+    product: function(options) {
+        return faker.random.array_element(faker.definitions.commerce.product_name.product, options);
     }
 
 };

lib/random.js

@@ -1,4 +1,4 @@
-var mersenne = require('../vendor/mersenne');
+var seedrandom = require('seedrandom');
 var faker = require('../index');
 
 var random = {
@@ -24,23 +24,40 @@ var random = {
           options.precision = 1;
         }
 
+        if (typeof options.seed === 'undefined') {
+            options.seed = null;
+        }
+
         // Make the range inclusive of the max value
         var max = options.max;
         if (max > 0) {
           max += options.precision;
-        } 
-
+        }
+
+        rng = seedrandom(options.seed);
+
+        max = max / options.precision;
+        var min = options.min/options.precision;
+
         var randomNumber = options.precision * Math.floor(
-          mersenne.rand(max / options.precision, options.min / options.precision));
+            Math.floor(rng() * (max - min) + min)
+        );
 
         return randomNumber;
 
     },
 
     // takes an array and returns a random element of the array
-    array_element: function (array) {
+    array_element: function (array, options) {
         array = array || ["a", "b", "c"];
-        var r = faker.random.number({ max: array.length - 1 });
+
+        options = options || {};
+
+        if (typeof options.seed === 'undefined') {
+            options.seed = null;
+        }
+
+        var r = faker.random.number({ max: array.length - 1, seed: options.seed });
         return array[r];
     },
 

package.json

@@ -28,5 +28,8 @@
     "sinon": "1.4.2",
     "vinyl-transform": "0.0.1"
   },
-  "main": "index.js"
+  "main": "index.js",
+  "dependencies": {
+    "seedrandom": "^2.3.11"
+  }
 }

test/commerce.unit.js

@@ -67,6 +67,31 @@ describe("commerce.js", function() {
             faker.commerce.productMaterial.restore();
             faker.commerce.product.restore();
         });
+
+        it("should return a seed product name when passed a seed", function() {
+            sinon.spy(faker.random, 'array_element');
+            sinon.spy(faker.commerce, 'productAdjective');
+            sinon.spy(faker.commerce, 'productMaterial');
+            sinon.spy(faker.commerce, 'product');
+
+            var seed = 1234;
+            var name = faker.commerce.productName({seed: seed });
+
+            assert.ok(name.split(' ').length >= 3);
+
+            assert.ok(faker.random.array_element.calledThrice);
+            assert.ok(faker.commerce.productAdjective.calledOnce);
+            assert.ok(faker.commerce.productMaterial.calledOnce);
+            assert.ok(faker.commerce.product.calledOnce);
+
+            faker.random.array_element.restore();
+            faker.commerce.productAdjective.restore();
+            faker.commerce.productMaterial.restore();
+            faker.commerce.product.restore();
+
+            // Test the seed has worked after checking the function call amounts, otherwise it will skew the numbers
+            assert.strictEqual(name, faker.commerce.productName({seed: seed }));
+        })
     });
 
     describe("price(min, max, dec, symbol", function() {

test/random.unit.js

@@ -60,8 +60,45 @@ describe("random.js", function () {
       assert.equal(opts.min, min);
       assert.equal(opts.max, max);
     });
+
+    it("should return a seeded random number if passed the seed parameter", function() {
+      var max = 100;
+      var seed = 1234;
+
+      assert.ok(faker.random.number({ max: max, seed: seed }) <= max);
+      assert.strictEqual(faker.random.number({ max: max, seed: seed }), faker.random.number({ max: max, seed: seed }));
+      assert.notStrictEqual(faker.random.number({ max: max }), faker.random.number({ max: max }));
+    });
   });
 
+    describe('array_element()', function() {
+        it("should return a default array if non passed in", function() {
+            var random = faker.random.array_element();
+            assert.ok(random);
+            assert.ok(_.contains(["a", "b", "c"], random));
+        });
+
+        it("should return a random array element", function() {
+            var array = [1, 2, 3, 4, 5];
+
+            var random = faker.random.array_element(array);
+
+            assert.ok(random);
+            assert.ok(_.contains(array, random));
+        });
+
+        it("should return a seeded array element", function() {
+            var array = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
+            var seed = 1234;
+
+            var random = faker.random.array_element(array, {seed: seed});
+
+            assert.ok(random);
+            assert.strictEqual(random, faker.random.array_element(array, {seed: seed}));
+            assert.ok(_.contains(array, random));
+        });
+    });
+
   describe('UUID', function() {
     it('should generate a valid UUID', function() {
       var UUID = faker.random.uuid();