add sinon and create a fake localStorage for jest

Author: AllenFang

config/localStorageMock.js

@@ -0,0 +1,23 @@
+class LocalStorageMock {
+  constructor() {
+    this.store = {};
+  }
+
+  clear() {
+    this.store = {};
+  }
+
+  getItem(key) {
+    return this.store[key];
+  }
+
+  setItem(key, value) {
+    this.store[key] = value.toString();
+  }
+
+  removeItem(key) {
+    delete this.store[key];
+  }
+};
+
+global.localStorage = new LocalStorageMock;

package.json

@@ -132,6 +132,7 @@
     "promise": "7.1.1",
     "react-dev-utils": "^0.5.2",
     "sass-loader": "^6.0.5",
+    "sinon": "^2.3.4",
     "style-loader": "0.13.1",
     "supertest": "~3.0.0",
     "url-loader": "0.5.7",
@@ -145,7 +146,8 @@
       "src/**/*.{js,jsx}"
     ],
     "setupFiles": [
-      "<rootDir>/config/polyfills.js"
+      "<rootDir>/config/polyfills.js",
+      "<rootDir>/config/localStorageMock.js"
     ],
     "testPathIgnorePatterns": [
       "<rootDir>[/\\\\](build|docs|node_modules|scripts|clicktests)[/\\\\]"