e2e: every test ends at the top of its window

tests/e2e/ext-specs/firefox-vpn.e2e.mjs

@@ -195,6 +195,9 @@ describe('Firefox VPN', function() {
   it('plays once allowed, its requests going the page\'s way', async function() {
     proxied.length = 0;
     const videoTab = await browser.getWindowHandle();
+    // Into the player of the case before (its page stays): a test no longer starts in the frame
+    // the one before ended in (setupGuard.mjs's root afterEach, 2026-10-11).
+    await enterPlayer();
     // A player in a page has no permissions API: its button opens the permissions page.
     await (await browser.$('.mainplayer .vpn_button')).click();
     let permsTab;

tests/e2e/setupGuard.mjs

@@ -29,7 +29,7 @@ export async function guardSetup(setup) {
 }
 
 // The configs' mochaOpts.rootHooks: the setup's failure first, the more useful reason, then
-// bidi.mjs's check.
+// bidi.mjs's check; and after every test, the window's top again.
 export const rootHooks = {
   beforeEach() {
     if (setupError) {
@@ -38,4 +38,19 @@ export const rootHooks = {
     }
     bidiRootHooks.beforeEach();
   },
+  // A test that ended in a frame (a player's) could leave the next test's first browser.url()
+  // waiting in a frame the navigation removed, until the 120 s timeout: on CI's Linux runner,
+  // each hang came in a test after one that ended in the player's frame, before its first step
+  // (autoplay-next-episode, main and #449, 2026-10-11; not every such test hung - a race in the
+  // driver). framed-player.e2e.mjs did this itself. A window or a session already gone is no
+  // news; anything else is said, so a reset that stops working shows.
+  async afterEach() {
+    try {
+      await globalThis.browser?.switchFrame(null);
+    } catch (e) {
+      if (!/no such (window|frame)|invalid session|session (deleted|not created)/i.test(String(e?.message || e))) {
+        console.warn('e2e: back to the window\'s top failed after a test:', e);
+      }
+    }
+  },
 };

tests/unit/e2eHarness.test.mjs

@@ -40,6 +40,20 @@ describe('guardSetup and rootHooks', () => {
     globalThis.browser = {isBidi: false, requestedCapabilities: {}};
     expect(() => rootHooks.beforeEach()).toThrow(/BiDi is not connected/);
   });
+
+  it('leave every test at the top of its window, also where that fails or no browser is up', async () => {
+    // A test that ended in a frame left the next one's first navigation waiting in it (2026-10-11).
+    const frames = [];
+    globalThis.browser = {switchFrame: async (to) => frames.push(to)};
+    await rootHooks.afterEach();
+    expect(frames).toEqual([null]);
+    globalThis.browser = {switchFrame: async () => {
+      throw new Error('no such window');
+    }};
+    await expect(rootHooks.afterEach()).resolves.toBeUndefined();
+    delete globalThis.browser;
+    await expect(rootHooks.afterEach()).resolves.toBeUndefined();
+  });
 });
 
 describe('writeFixture', () => {