1 files changed, 55 insertions, 0 deletions
diff --git a/browser/base/content/test/tabs/browser_addAdjacentNewTab.js b/browser/base/content/test/tabs/browser_addAdjacentNewTab.js
new file mode 100644
index 0000000000..c9b4b45ccc
--- /dev/null
+++ b/browser/base/content/test/tabs/browser_addAdjacentNewTab.js
@@ -0,0 +1,55 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+add_task(async function () {
+  await SpecialPowers.pushPrefEnv({
+    // Ensure we can wait for about:newtab to load.
+    set: [["browser.newtab.preload", false]],
+  });
+
+  const tab1 = await addTab();
+  const tab2 = await addTab();
+  const tab3 = await addTab();
+
+  const menuItemOpenANewTab = document.getElementById("context_openANewTab");
+
+  await BrowserTestUtils.switchTab(gBrowser, tab2);
+
+  is(tab1._tPos, 1, "First tab");
+  is(tab2._tPos, 2, "Second tab");
+  is(tab3._tPos, 3, "Third tab");
+
+  updateTabContextMenu(tab2);
+  is(menuItemOpenANewTab.hidden, false, "Open a new Tab is visible");
+
+  const newTabPromise = BrowserTestUtils.waitForNewTab(gBrowser);
+
+  // Open the tab context menu.
+  const contextMenu = document.getElementById("tabContextMenu");
+  // The TabContextMenu initializes its strings only on a focus or mouseover event.
+  // Calls focus event on the TabContextMenu early in the test.
+  gBrowser.selectedTab.focus();
+  const popupShownPromise = BrowserTestUtils.waitForEvent(
+    contextMenu,
+    "popupshown"
+  );
+  EventUtils.synthesizeMouseAtCenter(gBrowser.selectedTab, {
+    type: "contextmenu",
+    button: 2,
+  });
+  await popupShownPromise;
+
+  contextMenu.activateItem(menuItemOpenANewTab);
+
+  let newTab = await newTabPromise;
+
+  is(tab1._tPos, 1, "First tab");
+  is(tab2._tPos, 2, "Second tab");
+  is(newTab._tPos, 3, "Third tab");
+  is(tab3._tPos, 4, "Fourth tab");
+
+  BrowserTestUtils.removeTab(tab1);
+  BrowserTestUtils.removeTab(tab2);
+  BrowserTestUtils.removeTab(tab3);
+  BrowserTestUtils.removeTab(newTab);
+});