prepare coverage

package.json

@@ -11,9 +11,11 @@
     "babel-cli": "^6.18.0",
     "babel-core": "^6.18.0",
     "babel-loader": "^6.2.7",
+    "babel-plugin-istanbul": "^2.0.3",
     "babel-preset-es2015": "^6.18.0",
     "babel-register": "^6.18.0",
     "chai": "^3.5.0",
+    "cross-env": "^3.1.3",
     "css-loader": "^0.25.0",
     "doctoc": "^1.2.0",
     "express": "^4.14.0",
@@ -21,6 +23,7 @@
     "file-loader": "^0.9.0",
     "karma": "^1.3.0",
     "karma-chai": "^0.1.0",
+    "karma-coverage": "^1.1.1",
     "karma-mocha": "^1.2.0",
     "karma-mocha-reporter": "^2.2.0",
     "karma-phantomjs-launcher": "^1.0.2",
@@ -56,6 +59,11 @@
   ],
   "license": "MIT",
   "main": "lib",
+  "nyc": {
+    "exclude": [
+      "test/**/*.js"
+    ]
+  },
   "repository": {
     "url": "git@github.com:declandewet/vue-meta.git",
     "type": "git"
@@ -66,7 +74,7 @@
     "lint": "standard --verbose | snazzy",
     "prebuild": "rimraf lib",
     "pretest": "npm run lint",
-    "test": "karma start karma.conf.js",
+    "test": "cross-env NODE_ENV=test karma start karma.conf.js",
     "toc": "doctoc README.md --title '# Table of Contents'"
   },
   "standard": {