add istanbul and coverall integration

.travis.yml

@@ -1,10 +1,9 @@
 language: node_js
-
 node_js:
   - stable
-
 install:
   - npm install
-
 script:
-  - npm test
+  - npm run cover
+# Send coverage data to Coveralls
+after_script: "cat coverage/lcov.info | node_modules/coveralls/bin/coveralls.js"

package.json

@@ -4,7 +4,8 @@
   "description": "Convert number to string with locale separator",
   "main": "index.js",
   "scripts": {
-    "test": "mocha --reporter spec"
+    "test": "node_modules/.bin/mocha --reporter spec",
+    "cover": "node_modules/istanbul/lib/cli.js cover node_modules/mocha/bin/_mocha -- -R spec test/*"
   },
   "repository": {
     "type": "git",
@@ -25,6 +26,9 @@
   },
   "devDependencies": {
     "chai": "^4.1.2",
+    "coveralls": "^3.0.0",
+    "istanbul": "^0.4.5",
     "mocha": "^4.0.1"
-  }
+  },
+  "dependencies": {}
 }