karma.conf.js

var webpack = require('webpack');

module.exports = function (config) {
  config.set({

    browsers: [ process.env.CONTINUOUS_INTEGRATION ? 'Firefox' : 'Chrome' ],

    singleRun: false,

    frameworks: [ 'mocha' ],

    files: [
      'tests.webpack.js'
    ],

    preprocessors: {
      'tests.webpack.js': [ 'webpack', 'sourcemap' ]
    },

    reporters: [ 'mocha' ],

    webpack: {
      devtool: 'inline-source-map',
      module: {
        loaders: [
          { test: /\.(jpe?g|png|gif|svg)$/, loader: 'url', query: {limit: 10240} },
          { test: /\.js$/, exclude: /node_modules/, loaders: ['react-hot', 'babel?stage=0&optional=runtime']},
          { test: /\.json$/, loader: 'json-loader' },
          { test: /\.scss$/, loader: 'style!css?modules&importLoaders=2&sourceMap&localIdentName=[local]___[hash:base64:5]!autoprefixer?browsers=last 2 version!sass?outputStyle=expanded&sourceMap' }
        ]
      },
      resolve: {
        modulesDirectories: [
          'src',
          'node_modules'
        ],
        extensions: ['', '.json', '.js']
      },
      plugins: [
        // hot reload
        new webpack.HotModuleReplacementPlugin(),
        new webpack.IgnorePlugin(/\.json$/),
        new webpack.NoErrorsPlugin(),
        new webpack.DefinePlugin({
          __CLIENT__: true,
          __SERVER__: false,
          __DEVELOPMENT__: true,
          __DEVTOOLS__: false  // <-------- DISABLE redux-devtools HERE
        })
      ]
    },

    webpackServer: {
      noInfo: true
    }

  });
};