karma.conf.js

const { plugins, rules } = require('webpack-atoms');
const runBabel = require('./tools/run-babel');

const babelOptions = {
  ...runBabel.getConfig({ modules: false, test: true }),
  cacheDirectory: true
};

module.exports = config => {
  const { env } = process;

  config.set({
    frameworks: ['mocha', 'sinon-chai'],

    files: ['test/index.js'],

    preprocessors: {
      'test/index.js': ['webpack', 'sourcemap']
    },

    webpack: {
      module: {
        rules: [rules.js(babelOptions)]
      },
      plugins: [
        plugins.define({
          'process.env.NODE_ENV': JSON.stringify('test')
        })
      ],
      devtool: 'cheap-module-inline-source-map',
      stats: 'minimal'
    },

    webpackMiddleware: {
      noInfo: true
    },

    reporters: ['mocha', 'coverage'],

    mochaReporter: {
      output: 'autowatch'
    },

    coverageReporter: {
      type: 'lcov',
      dir: 'coverage'
    },

    customLaunchers: {
      ChromeCi: {
        base: 'Chrome',
        flags: ['--no-sandbox']
      }
    },

    browsers: env.BROWSER ? env.BROWSER.split(',') : ['Chrome'],

    singleRun: env.CONTINUOUS_INTEGRATION === 'true'
  });
};