add localStora mock

Author: jpavon

config/polyfills.js

@@ -28,3 +28,25 @@ Object.assign = require('object-assign');
 if (process.env.NODE_ENV === 'test') {
   require('raf').polyfill(global);
 }
+
+// localStorage
+const localStorageMock = (function() {
+  let store = {};
+
+  return {
+      getItem: function(key) {
+          return store[key] || null;
+      },
+      setItem: function(key, value) {
+          store[key] = value.toString();
+      },
+      clear: function() {
+          store = {};
+      }
+  };
+
+})();
+
+Object.defineProperty(window, 'localStorage', {
+   value: localStorageMock
+});