Add mocha as a dependency

Author: simonsmith

package.json

@@ -21,7 +21,8 @@
   "devDependencies": {
     "chai": "3.4.1",
     "eslint": "^1.10.3",
-    "eslint-config-airbnb": "^2.1.1"
+    "eslint-config-airbnb": "^2.1.1",
+    "mocha": "^2.3.4"
   },
   "scripts": {
     "lint": "eslint index.js test/*.js",