gecko-dev/dom/push/test/xpcshell/broadcast_handler.jsm

"use strict";

var EXPORTED_SYMBOLS = ["broadcastHandler"];

var broadcastHandler = {
  reset() {
    this.notifications = [];

    this.wasNotified = new Promise((resolve, reject) => {
      this.receivedBroadcastMessage = function() {
        resolve();
        this.notifications.push(Array.from(arguments));
      };
    });
  }
};