karma.conf.js

module.exports = config => {
  const karmaConfig = {
    frameworks: ["mocha", "chai", "sinon"],

    browserNoActivityTimeout: 60000,

    // list of files / patterns to load in the browser
    files: [
      "./node_modules/resemblejs/resemble.js",
      "./node_modules/hammer-simulator/index.js",
      "./node_modules/webvr-polyfill/build/webvr-polyfill.js",
      "./node_modules/webxr-polyfill/build/webxr-polyfill.js",
      "./test/hammer-simulator.run.js",
      "./test/unit/**/*.spec.js",
      {pattern: "./test/manual/img/**/*.*", watched: false, included: false, served: true},
    ],

    proxies: {
      "/images/": "/base/test/manual/img/"
    },

    client: {
      mocha: {
        opts: "./mocha.opts",
        timeout: "20000"
      }
    },

    webpack: {
      devtool: "inline-source-map",
      resolve: {
        extensions: [".ts", ".js"]
      },
      mode: "none",
      module: {
        rules: [
          {
            test: /\.js$/,
            exclude: /node_modules/,
            loader: "babel-loader",
            options: {
              "babelrc": false,
              "presets": [
                [
                  "@babel/preset-env", {
                    "targets": {"chrome": "55"},
                    "debug": true
                  }
                ]
              ],
              "plugins": [
                "@babel/plugin-transform-modules-commonjs",
                ["@babel/plugin-proposal-class-properties", {"loose": true}],
              ]
            }
          },
          {
            test: /\.ts$/,
            exclude: /node_modules/,
            use: {
              loader: "ts-loader",
              options: {
                transpileOnly: true,
                compilerOptions: {
                  module: "es5",
                },
              }
            }
          }
        ]
      }
    },

    // preprocess matching files before serving them to the browser
    // available preprocessors: https://npmjs.org/browse/keyword/karma-preprocessor
    preprocessors: {
      "./test/**/*.spec.js": config.coverage ? ["webpack"] : ["webpack", "sourcemap"]
    },

    browsers: [],
    customLaunchers: {
      ChromeHeadlessGL: {
        base: "Chrome",
        flags: [
          "--headless",
          "--hide-scrollbars",
          "--mute-audio",
          "--no-sandbox",
          "--disable-setuid-sandbox",
          // Without a remote debugging port, Google Chrome exits immediately.
          "--remote-debugging-port=9222",
          // Although --use-gl=osmesa is not specified. it need to install libosmesa in TRAVIS setting to test sucessfully
        ]
      }
    },
    reporters: ["mocha"],
    webpackMiddleware: {
      noInfo: true
    }
  };

  karmaConfig.browsers.push(config.chrome ? "Chrome" : "ChromeHeadlessGL");

  if (config.coverage) {
    karmaConfig.reporters.push("coverage-istanbul");
    karmaConfig.coverageIstanbulReporter = {
      reports: ["text-summary", "html", "lcovonly"],
      dir: "./coverage"
    };
    karmaConfig.webpack.module.rules.unshift({
      test: /\.ts$/,
      exclude: /(node_modules|test)/,
      loader: "istanbul-instrumenter-loader"
    });
    karmaConfig.singleRun = true;
  }

  config.set(karmaConfig);
};