1 files changed, 82 insertions, 0 deletions
diff --git a/browser/base/content/test/about/browser_aboutNewTab_bookmarksToolbarNewWindow.js b/browser/base/content/test/about/browser_aboutNewTab_bookmarksToolbarNewWindow.js
new file mode 100644
index 0000000000..19c990bbbc
--- /dev/null
+++ b/browser/base/content/test/about/browser_aboutNewTab_bookmarksToolbarNewWindow.js
@@ -0,0 +1,82 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+requestLongerTimeout(2);
+
+const testCases = [
+  {
+    name: "bookmarks_toolbar_shown_on_newtab_newTabEnabled",
+    newTabEnabled: true,
+  },
+  {
+    name: "bookmarks_toolbar_shown_on_newtab",
+    newTabEnabled: false,
+  },
+];
+
+async function test_bookmarks_toolbar_visibility({ newTabEnabled }) {
+  await SpecialPowers.pushPrefEnv({
+    set: [["browser.newtabpage.enabled", newTabEnabled]],
+  });
+
+  // Ensure the toolbar doesnt become visible at any point before the tab finishes loading
+
+  let url =
+    getRootDirectory(gTestPath).replace(
+      "chrome://mochitests/content",
+      "https://example.com"
+    ) + "slow_loading_page.sjs";
+
+  let startTime = Date.now();
+  let newWindowOpened = BrowserTestUtils.domWindowOpened();
+  let beforeShown = TestUtils.topicObserved("browser-window-before-show");
+
+  openTrustedLinkIn(url, "window");
+
+  let newWin = await newWindowOpened;
+  let slowSiteLoaded = BrowserTestUtils.firstBrowserLoaded(newWin, false);
+
+  function checkToolbarIsCollapsed(win, message) {
+    let toolbar = win.document.getElementById("PersonalToolbar");
+    ok(toolbar && toolbar.collapsed, message);
+  }
+
+  await beforeShown;
+  checkToolbarIsCollapsed(
+    newWin,
+    "Toolbar is initially hidden on the new window"
+  );
+
+  function onToolbarMutation() {
+    checkToolbarIsCollapsed(newWin, "Toolbar should remain collapsed");
+  }
+  let toolbarMutationObserver = new newWin.MutationObserver(onToolbarMutation);
+  toolbarMutationObserver.observe(
+    newWin.document.getElementById("PersonalToolbar"),
+    {
+      attributeFilter: ["collapsed"],
+    }
+  );
+
+  info("Waiting for the slow site to load");
+  await slowSiteLoaded;
+  info(`Window opened and slow site loaded in: ${Date.now() - startTime}ms`);
+
+  checkToolbarIsCollapsed(newWin, "Finally, the toolbar is still hidden");
+
+  toolbarMutationObserver.disconnect();
+  await BrowserTestUtils.closeWindow(newWin);
+}
+
+// Make separate tasks for each test case, so we get more useful stack traces on failure
+for (let testData of testCases) {
+  let tmp = {
+    async [testData.name]() {
+      info("testing with: " + JSON.stringify(testData));
+      await test_bookmarks_toolbar_visibility(testData);
+    },
+  };
+  add_task(tmp[testData.name]);
+}