Add basic http smoke test

- Add mocha dev dependency
- Add test to launch server and GET basic urls
- Add `yarn test` to travis

package.json

@@ -6,7 +6,8 @@
   "private": true,
   "scripts": {
     "dev": "webpack-dev-server --content-base static --mode development",
-    "build": "NODE_ENV=production webpack --mode production"
+    "build": "NODE_ENV=production webpack --mode production",
+    "test": "./node_modules/mocha/bin/mocha"
   },
   "dependencies": {
     "babel-polyfill": "^6.26.0",
@@ -37,6 +38,7 @@
     "file-loader": "^2.0.0",
     "html-webpack-plugin": "^3.2.0",
     "mini-css-extract-plugin": "^0.4.4",
+    "mocha": "^5.2.0",
     "node-sass": "^4.9.4",
     "redux-devtools": "^3.4.0",
     "sass-loader": "^7.1.0",