im.doctor/test/server/node_modules/mocha/lib/browser/tty.js

exports.isatty = function isatty() {
  return true;
};

exports.getWindowSize = function getWindowSize() {
  if ('innerHeight' in global) {
    return [global.innerHeight, global.innerWidth];
  }
  // In a Web Worker, the DOM Window is not available.
  return [640, 480];
};