text: import Emitter from 'events';
  
  let idCounter = 0;
  
  export default class MockWindow extends Emitter {
    constructor(...args) {
      super(...args);
      this.open = true;
      this.focused = false;
      this.id = idCounter++;
    }
  
    focus() {
      this.focused = true;
    }
  
    close() {
      this.open = false;
    }
  }
  