Bug 1538378 - Test that tabs.onCreated fires with active:true. r=mixedpuppy

Differential Revision: https://phabricator.services.mozilla.com/D24819

--HG--
extra : moz-landing-system : lando

browser/components/extensions/parent/ext-browser.js

@@ -471,8 +471,8 @@ class TabTracker extends TabTrackerBase {
           };
 
           // We need to delay sending this event until the next tick, since the
-          // tab could have been created with a lazy browser but still not have
-          // been assigned a SessionStore tab state with the URL and title.
+          // tab can become selected immediately after "TabOpen", then onCreated
+          // should be fired with `active: true`.
           Promise.resolve().then(() => {
             if (!event.originalTarget.parentNode) {
               // If the tab is already be destroyed, do nothing.

browser/components/extensions/test/browser/browser-common.ini

@@ -222,6 +222,7 @@ skip-if = (verify && !debug && (os == 'mac'))
 [browser_ext_tabs_move_window.js]
 [browser_ext_tabs_move_window_multiple.js]
 [browser_ext_tabs_move_window_pinned.js]
+[browser_ext_tabs_onCreated.js]
 [browser_ext_tabs_onHighlighted.js]
 [browser_ext_tabs_onUpdated.js]
 [browser_ext_tabs_onUpdated_filter.js]

browser/components/extensions/test/browser/browser_ext_tabs_onCreated.js

@@ -0,0 +1,26 @@
+/* -*- Mode: indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim: set sts=2 sw=2 et tw=80: */
+/* eslint-disable mozilla/no-arbitrary-setTimeout */
+"use strict";
+
+add_task(async function test_onCreated_active() {
+  let extension = ExtensionTestUtils.loadExtension({
+    manifest: {
+      "permissions": ["tabs"],
+    },
+    background: function() {
+      browser.tabs.onCreated.addListener(tab => {
+        browser.tabs.remove(tab.id);
+        browser.test.sendMessage("onCreated", tab);
+      });
+    },
+  });
+
+  await extension.startup();
+  BrowserOpenTab();
+
+  let tab = await extension.awaitMessage("onCreated");
+  is(true, tab.active, "Tab should be active");
+
+  await extension.unload();
+});