1 files changed, 52 insertions, 0 deletions
diff --git a/browser/base/content/test/general/browser_visibleTabs_tabPreview.js b/browser/base/content/test/general/browser_visibleTabs_tabPreview.js
new file mode 100644
index 0000000000..ecc7228d65
--- /dev/null
+++ b/browser/base/content/test/general/browser_visibleTabs_tabPreview.js
@@ -0,0 +1,52 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+add_task(async function test() {
+  await SpecialPowers.pushPrefEnv({
+    set: [["browser.ctrlTab.sortByRecentlyUsed", true]],
+  });
+
+  let [origTab] = gBrowser.visibleTabs;
+  let tabOne = BrowserTestUtils.addTab(gBrowser);
+  let tabTwo = BrowserTestUtils.addTab(gBrowser);
+
+  // test the ctrlTab.tabList
+  pressCtrlTab();
+  ok(ctrlTab.isOpen, "With 3 tab open, Ctrl+Tab opens the preview panel");
+  is(ctrlTab.tabList.length, 3, "Ctrl+Tab panel displays all visible tabs");
+  releaseCtrl();
+
+  gBrowser.showOnlyTheseTabs([origTab]);
+  pressCtrlTab();
+  ok(
+    !ctrlTab.isOpen,
+    "With 1 tab open, Ctrl+Tab doesn't open the preview panel"
+  );
+  releaseCtrl();
+
+  gBrowser.showOnlyTheseTabs([origTab, tabOne, tabTwo]);
+  pressCtrlTab();
+  ok(
+    ctrlTab.isOpen,
+    "Ctrl+Tab opens the preview panel after re-showing hidden tabs"
+  );
+  is(
+    ctrlTab.tabList.length,
+    3,
+    "Ctrl+Tab panel displays all visible tabs after re-showing hidden ones"
+  );
+  releaseCtrl();
+
+  // cleanup
+  gBrowser.removeTab(tabOne);
+  gBrowser.removeTab(tabTwo);
+});
+
+function pressCtrlTab(aShiftKey) {
+  EventUtils.synthesizeKey("VK_TAB", { ctrlKey: true, shiftKey: !!aShiftKey });
+}
+
+function releaseCtrl() {
+  EventUtils.synthesizeKey("VK_CONTROL", { type: "keyup" });
+}