--- a/browser/components/enterprisepolicies/tests/browser/browser_policy_extensions.js
+++ b/browser/components/enterprisepolicies/tests/browser/browser_policy_extensions.js
@@ -1,28 +1,29 @@
 /* Any copyright is dedicated to the Public Domain.
  * http://creativecommons.org/publicdomain/zero/1.0/ */
 "use strict";
 
 const addonID = "policytest@mozilla.com";
 
 add_task(async function test_addon_install() {
+  let installPromise = wait_for_addon_install();
   await setupPolicyEngineWithJson({
     "policies": {
       "Extensions": {
         "Install": [
           "http://mochi.test:8888/browser/browser/components/enterprisepolicies/tests/browser/policytest.xpi"
         ],
         "Locked": [
           addonID
         ]
       }
     }
   });
-  await wait_for_addon_install();
+  await installPromise;
   let addon = await AddonManager.getAddonByID(addonID);
   isnot(addon, null, "Addon not installed.");
 });
 
 add_task(async function test_addon_locked() {
   let tab = await BrowserTestUtils.openNewForegroundTab(gBrowser);
   await BrowserOpenAddonsMgr("addons://list/extension");
   // eslint-disable-next-line no-shadow