enable css to be directly imported/mocked into components for unit testing in jest

__mocks__/css.js

+module.exports = {};

jest.json

@@ -5,6 +5,9 @@
   ],
   "coverageDirectory": "<rootDir>/coverage",
   "coverageReporters": ["html", "lcov"],
+  "moduleNameMapper": {
+    "\\.css$": "<rootDir>/__mocks__/css.js"
+  },
   "setupFiles": [
     "<rootDir>/setupJest.js"
   ],

webpack.config.js

@@ -73,7 +73,7 @@ const baseConfig = [
         eslintLoaderConfig,
         babelLoaderConfig,
         {
-          test: /\.scss$/,
+          test: /\.s?css$/,
           use: [
             'style-loader', // creates style nodes from JS strings
             'css-loader', // translates CSS into CommonJS