Since plugin was published, there were a lot of changes in testing software. Be sure in most(all) cases you DON'T need this plugin for testing. I highly recommend you to use jest for testing, and use moduleNameMapper (identity-obj-proxy, etc) to mock CSS-Modules and other webpack loaders. This Babel 6 plugin allows you to use webpack loaders in Babel. It's now easy to run universal apps on the server without additional build steps, to create libraries as usual with babel src --out-dir lib command, to run tests without mocking-prebuilding source code. It just replaces require - import statements with webpack loaders results. Take a look at this Babel build output diff to get the idea.