test: count store listeners in memory leak test (#1853)

src/routes/_components/list/listStore.js

@@ -11,8 +11,8 @@ const listStore = new ListStore()
 
 listStore.computeForRealm('intersectionStates', {})
 
-if (process.browser && process.env.NODE_ENV !== 'production') {
-  window.listStore = listStore
+if (process.browser) {
+  window.__listStore = listStore // for debugging
 }
 
 export { listStore }

tests/spec/038-memory-leaks.js

@@ -10,7 +10,7 @@ import {
   homeNavButton, modalDialog, notificationsNavButton,
   scrollToStatus,
   scrollToTop,
-  settingsNavButton, sleep
+  settingsNavButton, sleep, getNumStoreListeners
 } from '../utils'
 import { loginAsFoobar } from '../roles'
 import { installDomListenerListener, getNumDomListeners } from '../spyDomListeners'
@@ -27,14 +27,17 @@ async function runMemoryLeakTest (t, firstStep, secondStep) {
   await sleep(1000)
   const numSyntheticListeners = await getNumSyntheticListeners()
   const numDomListeners = await getNumDomListeners()
+  const numStoreListeners = await getNumStoreListeners()
   await t
     .expect(numSyntheticListeners).typeOf('number')
     .expect(numDomListeners).typeOf('number')
+    .expect(numStoreListeners).typeOf('number')
   await secondStep()
   await sleep(1000)
   await t
     .expect(getNumSyntheticListeners()).eql(numSyntheticListeners)
     .expect(getNumDomListeners()).eql(numDomListeners)
+    .expect(getNumStoreListeners()).eql(numStoreListeners)
 }
 
 async function goToSettings (t) {

tests/utils.js

@@ -135,6 +135,19 @@ export const getNumSyntheticListeners = exec(() => {
     .reduce((a, b) => a + b, 0)
 })
 
+export const getNumStoreListeners = exec(() => {
+  function getStoreHandlers (storeName) {
+    return window[storeName] ? window[storeName]._handlers : {}
+  }
+
+  const values = 'values' // prevent Babel from transpiling Object.values
+  return Object[values](getStoreHandlers('__store'))
+    .concat(Object[values](getStoreHandlers('__listStore')))
+    .concat(Object[values](getStoreHandlers('__virtualListStore')))
+    .map(arr => arr.length)
+    .reduce((a, b) => a + b, 0)
+})
+
 export const getMediaScrollLeft = exec(() => document.querySelector('.media-scroll').scrollLeft || 0)
 
 export const getActiveElementClassList = exec(() =>