1 files changed, 40 insertions, 0 deletions
diff --git a/browser/base/content/test/tabs/browser_removeTabs_order.js b/browser/base/content/test/tabs/browser_removeTabs_order.js
new file mode 100644
index 0000000000..071cc03716
--- /dev/null
+++ b/browser/base/content/test/tabs/browser_removeTabs_order.js
@@ -0,0 +1,40 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const { sinon } = ChromeUtils.importESModule(
+  "resource://testing-common/Sinon.sys.mjs"
+);
+
+add_task(async function () {
+  let tab1 = await addTab();
+  let tab2 = await addTab();
+  let tab3 = await addTab();
+  let tabs = [tab1, tab2, tab3];
+
+  // Add a beforeunload event listener in one of the tabs; it should be called
+  // before closing any of the tabs.
+  await ContentTask.spawn(tab2.linkedBrowser, null, async function () {
+    content.window.addEventListener("beforeunload", function (event) {}, true);
+  });
+
+  let permitUnloadSpy = sinon.spy(tab2.linkedBrowser, "asyncPermitUnload");
+  let removeTabSpy = sinon.spy(gBrowser, "removeTab");
+
+  gBrowser.removeTabs(tabs);
+
+  Assert.ok(permitUnloadSpy.calledOnce, "permitUnload was called only once");
+  Assert.equal(
+    removeTabSpy.callCount,
+    tabs.length,
+    "removeTab was called for every tab"
+  );
+  Assert.ok(
+    permitUnloadSpy.lastCall.calledBefore(removeTabSpy.firstCall),
+    "permitUnload was called before for first removeTab call"
+  );
+
+  removeTabSpy.restore();
+  permitUnloadSpy.restore();
+});