Tests for restore:true error fix (#2)

Tests for WeeverApps#1

package.json

@@ -78,6 +78,7 @@
     "grunt-mocha-test": "^0.13.3",
     "jshint-stylish": "^2.2.1",
     "mocha": "^5.2.0",
-    "moment": "^2.23.0"
+    "moment": "^2.23.0",
+    "sinon": "7.3.1"
   }
 }

test/instatiation.spec.js

@@ -3,6 +3,7 @@
 //dependencies
 var expect = require('chai').expect;
 var path = require('path');
+var sinon = require('sinon');
 var kue = require(path.join(__dirname, '..', 'index'));
 var Queue;
 
@@ -71,3 +72,23 @@ describe('Queue Job Scheduler & Listener', function () {
   });
 
 });
+
+describe('Queue Job Scheduler & Listener Errors', function () {
+    var _getAllJobDataStub;
+    function fakeGetAllJobData (callback) {
+        callback(new Error('Some error occurred'));
+    }
+    beforeEach(function (done) {
+        _getAllJobDataStub = sinon.stub(kue.prototype, '_getAllJobData').callsFake(fakeGetAllJobData);
+        done();
+    });
+    afterEach(function (done) {
+        _getAllJobDataStub.restore();
+        done();
+    });
+    it('should not die with `TypeError: Cannot read property \'emit\' of undefined` when `restore:true`', function (done) {
+        Queue = kue.createQueue({restore: true});
+        expect(_getAllJobDataStub.called).to.be.true;
+        done();
+    });
+});