1 files changed, 51 insertions, 0 deletions
diff --git a/browser/base/content/test/tabs/browser_switch_by_scrolling.js b/browser/base/content/test/tabs/browser_switch_by_scrolling.js
new file mode 100644
index 0000000000..7d62234d7f
--- /dev/null
+++ b/browser/base/content/test/tabs/browser_switch_by_scrolling.js
@@ -0,0 +1,51 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+add_task(async function wheel_switches_tabs() {
+  Services.prefs.setBoolPref("toolkit.tabbox.switchByScrolling", true);
+
+  let newTab = await BrowserTestUtils.openNewForegroundTab(
+    gBrowser,
+    "about:blank"
+  );
+  await BrowserTestUtils.switchTab(gBrowser, () => {
+    EventUtils.synthesizeWheel(newTab, 4, 4, {
+      deltaMode: WheelEvent.DOM_DELTA_LINE,
+      deltaY: -1.0,
+    });
+  });
+  ok(!newTab.selected, "New tab should no longer be selected.");
+  BrowserTestUtils.removeTab(newTab);
+});
+
+add_task(async function wheel_switches_tabs_overflow() {
+  Services.prefs.setBoolPref("toolkit.tabbox.switchByScrolling", true);
+
+  let arrowScrollbox = gBrowser.tabContainer.arrowScrollbox;
+  let tabs = [];
+
+  while (!arrowScrollbox.hasAttribute("overflowing")) {
+    tabs.push(
+      await BrowserTestUtils.openNewForegroundTab(gBrowser, "about:blank")
+    );
+  }
+
+  let newTab = await BrowserTestUtils.openNewForegroundTab(
+    gBrowser,
+    "about:blank"
+  );
+  await BrowserTestUtils.switchTab(gBrowser, () => {
+    EventUtils.synthesizeWheel(newTab, 4, 4, {
+      deltaMode: WheelEvent.DOM_DELTA_LINE,
+      deltaY: -1.0,
+    });
+  });
+  ok(!newTab.selected, "New tab should no longer be selected.");
+
+  BrowserTestUtils.removeTab(newTab);
+  for (let tab of tabs) {
+    BrowserTestUtils.removeTab(tab);
+  }
+});