text: // Karma configuration
  const karmaWebpack = require('karma-webpack');
  
  module.exports = function createConfig(config) {
    const configuration = {
      // base path that will be used to resolve all patterns (eg. files, exclude)
      basePath: '',
  
      // frameworks to use
      // available frameworks: https://npmjs.org/browse/keyword/karma-adapter
      frameworks: ['mocha', 'sinon-chai'],
  
      client: {
        mocha: {
          ui: 'bdd',
        },
      },
  
      // list of files / patterns to load in the browser
      files: ['test/**/*.spec.js'],
  
      webpack: {
        devtool: 'inline-source-map',
  
        module: {
          loaders: [
            {
              test: /\.jsx?$/,
              loader: 'babel-loader',
              exclude: /node_modules/,
            },
          ],
        },
  
        externals: {
          cheerio: 'window',
          'react/addons': true,
          'react/lib/ExecutionEnvironment': true,
          'react/lib/ReactContext': true,
          'react-addons-test-utils': true,
        },
      },
  
      // list of files to exclude
      exclude: [],
  
      plugins: [
        karmaWebpack,
        'karma-mocha',
        'karma-sinon-chai',
        'karma-sourcemap-loader',
        'karma-chrome-launcher',
        'karma-coverage',
      ],
  
      // preprocess matching files before serving them to the browser
      // available preprocessors: https://npmjs.org/browse/keyword/karma-preprocessor
      preprocessors: {
        'src/**/*.js': ['webpack', 'sourcemap'],
        'test/**/*.js': ['webpack', 'sourcemap'],
      },
  
      // test results reporter to use
      // possible values: 'dots', 'progress'
      // available reporters: https://npmjs.org/browse/keyword/karma-reporter
      reporters: ['progress', 'coverage'],
  
      // web server port
      port: 9876,
  
      // enable / disable colors in the output (reporters and logs)
      colors: true,
  
      // level of logging
      // possible values: config.LOG_DISABLE || config.LOG_ERROR || config.LOG_WARN || config.LOG_INFO || config.LOG_DEBUG
      logLevel: config.LOG_INFO,
  
      // enable / disable watching file and executing tests whenever any file changes
      autoWatch: true,
  
      // start these browsers
      // available browser launchers: https://npmjs.org/browse/keyword/karma-launcher
      browsers: ['Chrome'],
  
      customLaunchers: {
        Chrome_travis_ci: {
          base: 'Chrome',
          flags: ['--no-sandbox'],
        },
      },
  
      // Continuous Integration mode
      // if true, Karma captures browsers, runs the tests and exits
      singleRun: false,
  
      // Concurrency level
      // how many browser should be started simultaneous
      concurrency: Infinity,
    };
  
    if (process.env.TRAVIS) {
      configuration.browsers = ['Chrome_travis_ci'];
    }
  
    config.set(configuration);
  };
  