reuse post-css configration for tests

frontend/webpack/test.js

@@ -4,7 +4,7 @@ const path = require('path');
 
 module.exports = {
   output: {
-    libraryTarget: 'commonjs2',
+    libraryTarget: 'commonjs2'
   },
   plugins: [
     config.__plugins['no-errors-plugin'],
@@ -14,24 +14,7 @@ module.exports = {
   module: {
     loaders: [{
       test: /\.css?$/,
-      loader: [
-        'style-loader', {
-          loader: 'css-loader',
-          options: {
-            modules: true,
-            importLoaders: 1
-          }
-        }, {
-          loader: 'postcss-loader',
-          options: {
-            plugins: function() {
-              return [
-                require('postcss-cssnext')
-              ];
-            }
-          }
-        }
-      ]
+      loader: 'style-loader!css-loader?modules&importLoaders=1&localIdentName=[name]__[local]___[hash:base64:5]!postcss-loader'
     }]
   }
 };