startupcache/test/browser/browser_startupcache_telemetry.js

   1 /* Any copyright is dedicated to the Public Domain.
   2    http://creativecommons.org/publicdomain/zero/1.0/ */
   3
   4 "use strict";
   5
   6 const LABELS_STARTUP_CACHE_REQUESTS = {
   7   HitMemory: 0,
   8   HitDisk: 1,
   9   Miss: 2,
  10 };
  11
  12 add_task(async function () {
  13   // Turn off tab preloading to avoid issues with RemoteController.js
  14   await SpecialPowers.pushPrefEnv({
  15     set: [["browser.newtab.preload", false]],
  16   });
  17
  18   Services.obs.notifyObservers(null, "startupcache-invalidate");
  19   Services.telemetry.getSnapshotForHistograms("main", true);
  20   let newWin = await BrowserTestUtils.openNewBrowserWindow();
  21   let snapshot = Services.telemetry.getSnapshotForHistograms("main", true);
  22   function histValue(label) {
  23     return snapshot.parent.STARTUP_CACHE_REQUESTS.values[label] || 0;
  24   }
  25   Assert.equal(histValue(LABELS_STARTUP_CACHE_REQUESTS.HitMemory), 0);
  26   Assert.equal(histValue(LABELS_STARTUP_CACHE_REQUESTS.HitDisk), 0);
  27   Assert.notEqual(histValue(LABELS_STARTUP_CACHE_REQUESTS.Miss), 0);
  28   await BrowserTestUtils.closeWindow(newWin);
  29
  30   newWin = await BrowserTestUtils.openNewBrowserWindow();
  31   snapshot = Services.telemetry.getSnapshotForHistograms("main", true);
  32   Assert.notEqual(histValue(LABELS_STARTUP_CACHE_REQUESTS.HitMemory), 0);
  33   Assert.equal(histValue(LABELS_STARTUP_CACHE_REQUESTS.HitDisk), 0);
  34
  35   // Here and below, 50 is just a nice round number that should be well over
  36   // what we should observe under normal circumstances, and well under what
  37   // we should see if something is seriously wrong. It won't catch everything,
  38   // but it's better than nothing, and better than a test that cries wolf.
  39   Assert.less(histValue(LABELS_STARTUP_CACHE_REQUESTS.Miss), 50);
  40   await BrowserTestUtils.closeWindow(newWin);
  41
  42   Services.obs.notifyObservers(null, "startupcache-invalidate", "memoryOnly");
  43   newWin = await BrowserTestUtils.openNewBrowserWindow();
  44   snapshot = Services.telemetry.getSnapshotForHistograms("main", true);
  45   Assert.less(histValue(LABELS_STARTUP_CACHE_REQUESTS.HitMemory), 50);
  46   Assert.notEqual(histValue(LABELS_STARTUP_CACHE_REQUESTS.HitDisk), 0);
  47   // Some misses can come through - just ensure it's a small number
  48   Assert.less(histValue(LABELS_STARTUP_CACHE_REQUESTS.Miss), 50);
  49   await BrowserTestUtils.closeWindow(newWin);
  50 });