Add playwright test to check EW error screen dismiss on room switch

playwright/widget/call-error-room-switch.spec.ts

@@ -0,0 +1,64 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+import { expect, test } from "@playwright/test";
+
+import { widgetTest } from "../fixtures/widget-user.ts";
+import { TestHelpers } from "./test-helpers.ts";
+
+widgetTest.skip(
+  ({ browserName }) => browserName === "firefox",
+  "Widget specs only run on Chromium, see simple-create.spec.ts",
+);
+
+widgetTest(
+  "Switching rooms away from a crashed call dismisses it for good",
+  async ({ asWidget }) => {
+    test.slow();
+    const { brooks } = asWidget;
+    const page = brooks.page;
+    const call = page.locator('iframe[title="Element Call"]');
+    const callFrame = call.contentFrame();
+
+    // Somewhere to switch to once the call has crashed
+    await TestHelpers.createRoom("Other Room", page);
+    await TestHelpers.switchToRoomNamed(page, "Welcome Room");
+
+    await TestHelpers.startCallInCurrentRoom(page);
+    // A dev server compiles the widget on first load
+    await expect(callFrame.getByTestId("lobby_joinCall")).toBeVisible({
+      timeout: 30000,
+    });
+    await TestHelpers.joinCallFromLobby(page);
+    await expect(
+      callFrame.getByRole("button", { name: "End call" }),
+    ).toBeVisible();
+
+    // Crash the call from its developer settings
+    await callFrame.getByRole("button", { name: "Settings" }).click();
+    await callFrame.getByRole("tab", { name: "Preferences" }).click();
+    await callFrame.getByText("Developer mode", { exact: true }).check();
+    await callFrame.getByRole("tab", { name: "Developer" }).click();
+    await callFrame.getByRole("button", { name: "Throw test error" }).click();
+    await expect(callFrame.getByText("Something went wrong")).toBeVisible();
+
+    // Showing the call collapses the room list
+    await TestHelpers.expandRoomList(page);
+    await TestHelpers.switchToRoomNamed(page, "Other Room");
+    await expect(
+      page.getByRole("banner").getByRole("heading", { name: "Other Room" }),
+    ).toBeVisible();
+
+    // The crashed call is gone and stays gone: no restart, no reconnect
+    await expect(call).toHaveCount(0);
+    await page.waitForTimeout(5000);
+    await expect(call).toHaveCount(0);
+    await expect(
+      page.getByRole("banner").getByRole("heading", { name: "Other Room" }),
+    ).toBeVisible();
+  },
+);