test(electron): smoke test as the regression gate for the desktop shell

Phase 1 step 2 of VNCprodbuild. e2e/electron-smoke.spec.ts uses Playwright's
_electron.launch() to boot the real skeleton (dist-electron/main.js from
step 1) and asserts:
  - the login screen renders (same input[type="text"]/[type="password"]
    selectors as e2e/login.spec.ts's browser-based check)
  - zero uncaught page errors fire during load

Sets JMAP_SERVER_URL (any non-empty value) so the app reaches
lib/setup/state.ts's "env-managed" state and serves the normal login screen
instead of 302ing to the first-run /setup wizard - no live mail server or
mock JMAP build flag needed just to prove the shell renders.

playwright.electron.config.ts is deliberately separate from
playwright.config.ts: it has no `webServer` block, since this suite's app
boots its own server and would otherwise race pointlessly with `npm run dev`
starting on :3000 for the browser-based e2e/*.spec.ts suite.

Wired as `npm run test:electron`. Verified green locally (2 passed) after
`npm run build:standalone && npm run build:electron`; every later step in
the Electron rollout must keep this passing before moving on.

.gitignore

@@ -42,6 +42,10 @@ yarn-error.log*
 /dist-electron/
 /dist-electron-builds/
 
+# playwright output
+/test-results/
+/playwright-report/
+
 # typescript
 *.tsbuildinfo
 next-env.d.ts

e2e/electron-smoke.spec.ts

@@ -0,0 +1,62 @@
+import { test, expect, _electron as electron } from '@playwright/test';
+import type { ElectronApplication, Page } from '@playwright/test';
+import path from 'node:path';
+
+// Regression gate for the Electron desktop shell (electron/main.ts +
+// electron/preload.ts). Launches the real skeleton - the same standalone
+// Next.js server artifact the Dockerfile produces, booted as a child
+// process by main.ts, with a real BrowserWindow on top - and asserts the
+// login screen renders with zero uncaught page errors. Every later step in
+// the Electron rollout (notification bridge, realtime sync, packaging) must
+// keep this green; run it before touching anything else.
+//
+// Requires `npm run build:standalone && npm run build:electron` to have run
+// first (see package.json's `electron:dev`/`test:electron` scripts, which
+// this suite assumes but does not itself trigger, matching how
+// playwright.config.ts's browser suite assumes `npm run build` for its own
+// prod-mode runs).
+const projectRoot = path.resolve(__dirname, '..');
+
+test.describe('Electron desktop shell', () => {
+  let electronApp: ElectronApplication;
+  let window: Page;
+  const pageErrors: Error[] = [];
+
+  test.beforeAll(async () => {
+    electronApp = await electron.launch({
+      args: [projectRoot],
+      env: {
+        ...process.env,
+        // Bypass the first-run setup wizard (lib/setup/state.ts's
+        // "bootstrap" state, which 302s everything to /setup) without
+        // needing a reachable JMAP server just to prove the login screen
+        // renders - any non-empty JMAP_SERVER_URL is enough to reach
+        // "env-managed" state and serve the normal app shell.
+        JMAP_SERVER_URL: 'https://stalwart.sandbox.vnc.de',
+        SESSION_SECRET: 'electron-smoke-test-not-for-production',
+        NODE_ENV: 'production',
+      },
+    });
+
+    window = await electronApp.firstWindow();
+    window.on('pageerror', (error) => {
+      pageErrors.push(error);
+    });
+    await window.waitForLoadState('domcontentloaded');
+  });
+
+  test.afterAll(async () => {
+    await electronApp?.close();
+  });
+
+  test('boots the standalone server and renders the login screen', async () => {
+    // Same selectors as e2e/login.spec.ts's browser-based check - the
+    // shell should render the identical login form, not a different view.
+    await expect(window.locator('input[type="text"]')).toBeVisible({ timeout: 20000 });
+    await expect(window.locator('input[type="password"]')).toBeVisible();
+  });
+
+  test('produces zero uncaught page errors', () => {
+    expect(pageErrors).toEqual([]);
+  });
+});

playwright.electron.config.ts

@@ -0,0 +1,21 @@
+import { defineConfig } from '@playwright/test';
+
+// Separate from playwright.config.ts on purpose: the Electron smoke suite
+// launches its own app (which boots its own standalone Next.js server via
+// electron/main.ts - see scripts/build-electron.mjs), so it must NOT inherit
+// the main config's `webServer` (which starts `npm run dev` on :3000 for the
+// browser-based e2e/*.spec.ts suite) - the two would fight over nothing but
+// still waste time starting a server this suite never touches.
+export default defineConfig({
+  testDir: './e2e',
+  testMatch: 'electron-smoke.spec.ts',
+  timeout: 60000,
+  retries: 0,
+  use: {
+    trace: 'retain-on-failure',
+  },
+  // Electron tests drive their own app windows via the `_electron` fixture,
+  // not a browser project - one worker keeps main-process/server startup
+  // logs and any zombie processes easy to reason about.
+  workers: 1,
+});