diff --git a/toolkit/components/extensions/test/xpcshell/test_ext_runtime_onInstalled_and_onStartup.js b/toolkit/components/extensions/test/xpcshell/test_ext_runtime_onInstalled_and_onStartup.js
index 91b64f58da74..e3f78a5de4f5 100644
--- a/toolkit/components/extensions/test/xpcshell/test_ext_runtime_onInstalled_and_onStartup.js
+++ b/toolkit/components/extensions/test/xpcshell/test_ext_runtime_onInstalled_and_onStartup.js
@@ -21,7 +21,11 @@ AddonTestUtils.init(this);
 // Allow for unsigned addons.
 AddonTestUtils.overrideCertDB();
 
-createAppInfo("xpcshell@tests.mozilla.org", "XPCShell", "1", "42");
+createAppInfo("xpcshell@tests.mozilla.org", "XPCShell", "42", "42");
+
+// Ensure that the background page is automatically started after using
+// promiseStartupManager.
+Services.prefs.setBoolPref("extensions.webextensions.background-delayed-startup", false);
 
 function background() {
   let onInstalledDetails = null;
@@ -169,7 +173,7 @@ add_task(async function test_should_fire_on_addon_update() {
 add_task(async function test_should_fire_on_browser_update() {
   const EXTENSION_ID = "test_runtime_on_installed_browser_update@tests.mozilla.org";
 
-  await promiseStartupManager();
+  await promiseStartupManager("1");
 
   let extension = ExtensionTestUtils.loadExtension({
     useAddonManager: "permanent",
@@ -193,8 +197,8 @@ add_task(async function test_should_fire_on_browser_update() {
     onInstalledReason: "install",
   });
 
+  // Restart the browser.
   await promiseRestartManager("1");
-
   await extension.awaitStartup();
 
   await expectEvents(extension, {
diff --git a/toolkit/components/extensions/test/xpcshell/xpcshell-common.ini b/toolkit/components/extensions/test/xpcshell/xpcshell-common.ini
index 89285f024c00..257c08ead352 100644
--- a/toolkit/components/extensions/test/xpcshell/xpcshell-common.ini
+++ b/toolkit/components/extensions/test/xpcshell/xpcshell-common.ini
@@ -93,7 +93,6 @@ skip-if = os == "android" && debug
 [test_ext_runtime_getPlatformInfo.js]
 [test_ext_runtime_id.js]
 [test_ext_runtime_onInstalled_and_onStartup.js]
-skip-if = true # bug 1315829
 [test_ext_runtime_sendMessage.js]
 [test_ext_runtime_sendMessage_errors.js]
 [test_ext_runtime_sendMessage_no_receiver.js]
diff --git a/toolkit/mozapps/extensions/internal/AddonTestUtils.jsm b/toolkit/mozapps/extensions/internal/AddonTestUtils.jsm
index 6936f3c82b07..7be5208f6692 100644
--- a/toolkit/mozapps/extensions/internal/AddonTestUtils.jsm
+++ b/toolkit/mozapps/extensions/internal/AddonTestUtils.jsm
@@ -802,7 +802,7 @@ var AddonTestUtils = {
 
     // Wait for all add-ons to finish starting up before resolving.
     const {XPIProvider} = ChromeUtils.import("resource://gre/modules/addons/XPIProvider.jsm", null);
-    await Promise.all(Array.from(XPIProvider.activeAddons,
+    await Promise.all(Array.from(XPIProvider.activeAddons.values(),
                                  addon => addon.startupPromise));
   },