--- a/toolkit/components/extensions/test/xpcshell/test_ext_experiments.js
+++ b/toolkit/components/extensions/test/xpcshell/test_ext_experiments.js
@@ -4,17 +4,17 @@
 
 XPCOMUtils.defineLazyModuleGetter(this, "AddonManager",
                                   "resource://gre/modules/AddonManager.jsm");
 
 function promiseAddonStartup() {
   const {Management} = Cu.import("resource://gre/modules/Extension.jsm");
 
   return new Promise(resolve => {
-    let listener = (extension) => {
+    let listener = (evt, extension) => {
       Management.off("startup", listener);
       resolve(extension);
     };
 
     Management.on("startup", listener);
   });
 }
 

--- a/toolkit/mozapps/extensions/test/xpcshell/test_delay_update_webextension.js
+++ b/toolkit/mozapps/extensions/test/xpcshell/test_delay_update_webextension.js
@@ -28,17 +28,17 @@ mapFile("/data/test_no_update.json", tes
 testserver.registerDirectory("/addons/", do_get_file("addons"));
 
 createAppInfo("xpcshell@tests.mozilla.org", "XPCShell", "1", "42");
 
 const { Management } = Components.utils.import("resource://gre/modules/Extension.jsm", {});
 
 function promiseWebExtensionStartup() {
   return new Promise(resolve => {
-    let listener = (extension) => {
+    let listener = (event, extension) => {
       Management.off("startup", listener);
       resolve(extension);
     };
 
     Management.on("startup", listener);
   });
 }
 

--- a/toolkit/mozapps/extensions/test/xpcshell/test_webextension.js
+++ b/toolkit/mozapps/extensions/test/xpcshell/test_webextension.js
@@ -13,17 +13,17 @@ profileDir.append("extensions");
 
 createAppInfo("xpcshell@tests.mozilla.org", "XPCShell", "1", "42");
 startupManager();
 
 const { GlobalManager, Management } = Components.utils.import("resource://gre/modules/Extension.jsm", {});
 
 function promiseAddonStartup() {
   return new Promise(resolve => {
-    let listener = (extension) => {
+    let listener = (evt, extension) => {
       Management.off("startup", listener);
       resolve(extension);
     };
 
     Management.on("startup", listener);
   });
 }
 

--- a/toolkit/mozapps/extensions/test/xpcshell/test_webextension_icons.js
+++ b/toolkit/mozapps/extensions/test/xpcshell/test_webextension_icons.js
@@ -10,17 +10,17 @@ profileDir.create(AM_Ci.nsIFile.DIRECTOR
 
 createAppInfo("xpcshell@tests.mozilla.org", "XPCShell", "1", "42");
 startupManager();
 
 const { Management } = Components.utils.import("resource://gre/modules/Extension.jsm", {});
 
 function promiseAddonStartup() {
   return new Promise(resolve => {
-    let listener = (extension) => {
+    let listener = (evt, extension) => {
       Management.off("startup", listener);
       resolve(extension);
     };
 
     Management.on("startup", listener);
   });
 }