title: How to configure create-react-app with webpack and how it is running test?
body: <p>I am trying to play with create-react-app, after doing this, I found the following </p>
  
  <p>1) How it is running test? which test framework it is using?
  2) there is no webpack.conf.js, although webpack is used?</p>
  
  <p>any other framework I could use beyond create-react-app, I have a feeling it is not easy to use?</p>