karma.conf.js

const path = require('path');
const webpackConfig = require('./webpack.config');

module.exports = config => {
  const files = [{ pattern: 'src/index.spec.ts' }];
  const webpackOptions = { hmr: false, test: true, coverage: false };
  const buildPath = path.join(__dirname, 'dist');

  config.set({
    preprocessors: {
      '**/index.spec.ts': ['webpack', 'sourcemap'],
      '**/index.ts': ['coverage'],
    },
    browsers: ['ChromeCustom'],
    customLaunchers: {
      ChromeCustom: {
        base: 'ChromeHeadless',
        // We must disable the Chrome sandbox when running Chrome inside Docker (Chrome's sandbox needs
        // more permissions than Docker allows by default)
        flags: ['--no-sandbox'],
      },
    },
    frameworks: ['jasmine'],
    reporters: ['progress'],
    mime: {
      'text/x-typescript': ['ts', 'tsx'],
    },
    port: 9876,
  });

  if (process.argv.indexOf('--coverage') !== -1) {
    const testResultsOutput = `${__dirname}/~testresults`;
    webpackOptions.coverage = true;
    config.set({
      reporters: ['coverage', 'remap-coverage'],
      coverageReporter: {
        type: 'in-memory',
      },
      remapCoverageReporter: {
        text: null,
        // html: `${testResultsOutput}/coverage`
      },
    });
  } else {
    files.unshift({
      pattern: path.join(buildPath, 'libs.js'),
      watched: false,
    });
  }

  const webpackConfiguration = webpackConfig(webpackOptions);

  config.set({
    files: files,
    webpack: webpackConfiguration,
    webpackMiddleware: {
      stats: webpackConfiguration.stats,
    },
  });
};