1 files changed, 41 insertions, 0 deletions
diff --git a/browser/base/content/test/tabs/browser_newwindow_tabstrip_overflow.js b/browser/base/content/test/tabs/browser_newwindow_tabstrip_overflow.js
new file mode 100644
index 0000000000..f2577cc8b2
--- /dev/null
+++ b/browser/base/content/test/tabs/browser_newwindow_tabstrip_overflow.js
@@ -0,0 +1,41 @@
+/* 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/. */
+
+const DEFAULT_THEME = "default-theme@mozilla.org";
+
+async function selectTheme(id) {
+  let theme = await AddonManager.getAddonByID(id || DEFAULT_THEME);
+  await theme.enable();
+}
+
+registerCleanupFunction(() => {
+  return selectTheme(null);
+});
+
+add_task(async function withoutLWT() {
+  let win = await BrowserTestUtils.openNewBrowserWindow();
+  ok(
+    !win.gBrowser.tabContainer.hasAttribute("overflow"),
+    "tab container not overflowing"
+  );
+  ok(
+    !win.gBrowser.tabContainer.arrowScrollbox.hasAttribute("overflowing"),
+    "arrow scrollbox not overflowing"
+  );
+  await BrowserTestUtils.closeWindow(win);
+});
+
+add_task(async function withLWT() {
+  await selectTheme("firefox-compact-light@mozilla.org");
+  let win = await BrowserTestUtils.openNewBrowserWindow();
+  ok(
+    !win.gBrowser.tabContainer.hasAttribute("overflow"),
+    "tab container not overflowing"
+  );
+  ok(
+    !win.gBrowser.tabContainer.arrowScrollbox.hasAttribute("overflowing"),
+    "arrow scrollbox not overflowing"
+  );
+  await BrowserTestUtils.closeWindow(win);
+});