Improvement tests (#76)

* Improvement tests

* Add Istanbul: Code Coverage Tool

* Fix tests

* Uid test

* Removed istanbul in the depencies

package.json

@@ -42,13 +42,15 @@
     "storybook": "start-storybook -p 6006",
     "flow": "flow",
     "precommit": "npm run test",
-    "prepush": "npm run test"
+    "prepush": "npm run test",
+    "coverage": "cross-env NODE_ENV=test nyc --reporter=lcov --reporter=text mocha --compilers js:babel-register tests/**/*.js"
   },
   "devDependencies": {
     "@storybook/react": "^3.1.9",
     "babel-core": "^6.7.4",
     "babel-eslint": "^8.0.2",
     "babel-plugin-external-helpers": "^6.22.0",
+    "babel-plugin-istanbul": "^4.1.5",
     "babel-plugin-transform-es2015-modules-umd": "^6.6.5",
     "babel-polyfill": "^6.7.4",
     "babel-preset-env": "^1.6.1",
@@ -67,9 +69,12 @@
     "eslint-plugin-react": "^7.5.1",
     "flow-bin": "^0.59.0",
     "husky": "^0.14.3",
-    "jsdom": "^11.1.0",
+    "istanbul": "^0.4.5",
+    "jsdom": "11.6.0",
+    "jsdom-global": "3.0.2",
     "mocha": "^4.0.1",
     "nodemon": "^1.9.1",
+    "nyc": "^11.4.1",
     "prettier": "^1.6.1",
     "react": "^16.1.1",
     "react-addons-test-utils": "^15.0.0",