add test for Plotly.version === pkg.version

Author: etpinard

test/jasmine/tests/plot_api_test.js

@@ -5,11 +5,18 @@ var Lib = require('@src/lib');
 var Scatter = require('@src/traces/scatter');
 var Bar = require('@src/traces/bar');
 var Legend = require('@src/components/legend');
+var pkg = require('../../../package.json');
 
 
 describe('Test plot api', function() {
     'use strict';
 
+    describe('Plotly.version', function() {
+        it('should be the same as in the package.json', function() {
+            expect(Plotly.version).toEqual(pkg.version);
+        });
+    });
+
     describe('Plotly.restyle', function() {
         beforeEach(function() {
             spyOn(Plotly, 'plot');