MM-63669 E2E/Playwright: Move "e2e-tests/playwright/test" to "e2e-tests/playwright" folder (#30647)

* move "e2e-tests/playwright/test" to  "e2e-tests/playwright/test" and expose "ensurePluginsLoaded"

* add test setup, and expose ensurePluginsLoaded and ensureServerDeployment to pw

e2e-tests/playwright/specs/functional/channels/notifications/notification.spec.ts

@@ -0,0 +1,56 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+import {expect, test} from '@mattermost/playwright-lib';
+
+test('MM-T483 Channel-wide mentions with uppercase letters', async ({pw, headless, browserName}) => {
+    test.skip(
+        headless && browserName !== 'firefox',
+        'Works across browsers and devices, except in headless mode, where stubbing the Notification API is supported only in Firefox and WebKit.',
+    );
+
+    // Initialize setup and get the required users and team
+    const {team, adminUser, user} = await pw.initSetup();
+
+    // Log in as the admin in one browser session and navigate to the "town-square" channel
+    const {page: adminPage, channelsPage: adminChannelsPage} = await pw.testBrowser.login(adminUser);
+    await adminChannelsPage.goto(team.name, 'town-square');
+    await adminChannelsPage.toBeVisible();
+
+    // Stub the Notification in the admin's browser to capture notifications
+    await pw.stubNotification(adminPage, 'granted');
+
+    // Log in as the regular user in a separate browser and navigate to the "off-topic" channel
+    const {channelsPage: otherChannelsPage} = await pw.testBrowser.login(user);
+    await otherChannelsPage.goto(team.name, 'off-topic');
+    await otherChannelsPage.toBeVisible();
+
+    // Post a channel-wide mention message "@ALL" in uppercase from the user's browser
+    const message = `@ALL good morning, ${team.name}!`;
+    await otherChannelsPage.postMessage(message);
+
+    // Wait for a notification to be received in the admin's browser and verify its content
+    const notifications = await pw.waitForNotification(adminPage);
+    expect(notifications.length).toBe(1);
+
+    const notification = notifications[0];
+    expect(notification.title).toBe('Off-Topic');
+    expect(notification.body).toBe(`@${user.username}: ${message}`);
+    expect(notification.tag).toBe(`@${user.username}: ${message}`);
+    expect(notification.icon).toContain('.png');
+    expect(notification.requireInteraction).toBe(false);
+    expect(notification.silent).toBe(false);
+
+    // Verify the last post as viewed by the regular user in the "off-topic" channel contains the message and is highlighted
+    const otherLastPost = await otherChannelsPage.centerView.getLastPost();
+    await otherLastPost.toContainText(message);
+    await expect(otherLastPost.container.locator('.mention--highlight')).toBeVisible();
+    await expect(otherLastPost.container.locator('.mention--highlight').getByText('@ALL')).toBeVisible();
+
+    // Admin navigates to the "off-topic" channel and verifies the message is posted and highlighted correctly
+    await adminChannelsPage.goto(team.name, 'off-topic');
+    const adminLastPost = await adminChannelsPage.centerView.getLastPost();
+    await adminLastPost.toContainText(message);
+    await expect(adminLastPost.container.locator('.mention--highlight')).toBeVisible();
+    await expect(adminLastPost.container.locator('.mention--highlight').getByText('@ALL')).toBeVisible();
+});