Fail Playwright tests on warnings/errors being thrown to the console

frontend/editor/src/core/tests/enterprise/license-and-features.spec.ts

@@ -1,4 +1,4 @@
-import { test, expect } from "@playwright/test";
+import { test, expect } from "@app/tests/helpers/test-base";
 import { ensureCookieConsent } from "@app/tests/helpers/login";
 import { bypassOnboarding } from "@app/tests/helpers/api-stubs";
 import { openSettings } from "@app/tests/helpers/ui-helpers";

frontend/editor/src/core/tests/enterprise/oauth-keycloak-login.spec.ts

@@ -1,4 +1,4 @@
-import { test, expect } from "@playwright/test";
+import { test, expect } from "@app/tests/helpers/test-base";
 import { ensureCookieConsent } from "@app/tests/helpers/login";
 import { bypassOnboarding } from "@app/tests/helpers/api-stubs";
 

frontend/editor/src/core/tests/enterprise/saml-keycloak-login.spec.ts

@@ -1,4 +1,4 @@
-import { test, expect } from "@playwright/test";
+import { test, expect } from "@app/tests/helpers/test-base";
 import { ensureCookieConsent } from "@app/tests/helpers/login";
 import { bypassOnboarding } from "@app/tests/helpers/api-stubs";
 

frontend/editor/src/core/tests/helpers/stub-test-base.ts

@@ -1,8 +1,7 @@
-import { test as base, expect } from "@playwright/test";
+import { test as base, expect } from "@app/tests/helpers/test-base";
 import {
   bypassOnboarding,
   mockAppApis,
-  seedCookieConsent,
   skipOnboarding,
   type MockAppApiOptions,
 } from "@app/tests/helpers/api-stubs";
@@ -57,7 +56,8 @@ export const test = base.extend<StubFixtures>({
   seedJwt: [false, { option: true }],
 
   page: async ({ page, stubOptions, autoGoto, seedJwt }, use) => {
-    await seedCookieConsent(page);
+    // `page` comes from test-base, which has already seeded cookie consent
+    // and attached the console-error recorder before any navigation runs.
     if (seedJwt) {
       // Logged-in users hit the orchestrator path that surfaces the
       // analytics opt-in / MFA prompts — use the stronger bypass-all flag

frontend/editor/src/core/tests/helpers/test-base.ts

@@ -1,14 +1,216 @@
-import { test as base, expect } from "@playwright/test";
+import { test as base, expect, type Page } from "@playwright/test";
 
 /**
- * Custom test fixture that auto-dismisses the cookie consent banner
- * before every test. The banner (#cc-main) overlays the page and
- * intercepts pointer events, causing click timeouts across all tests.
+ * Console message types that should fail the test if they appear.
+ * `console.error()` -> type "error", `console.warn()` -> type "warning".
+ */
+const FAILING_CONSOLE_TYPES = new Set(["error", "warning"]);
+
+/**
+ * Patterns ignored globally on every page. Keep this list small and
+ * well-justified — each entry suppresses a genuine console warning for
+ * every test, which means we lose detection of regressions in that
+ * surface. Only add things that:
+ *
+ *   - fire on first page render of *every* test (so per-test
+ *     suppression would just be ceremony), AND
+ *   - are environmental noise (third-party CDN, dev-server quirk,
+ *     known init-order quirk) rather than something a test could
+ *     reasonably assert.
+ *
+ * Anything that fires only on specific flows belongs in an inline
+ * `expectConsoleError` / `suppressConsoleErrors` at the call site.
+ */
+const GLOBAL_IGNORE_PATTERNS: RegExp[] = [
+  // Stripe.js logs an HTTP warning when loaded over localhost. Third-party,
+  // expected in dev, no production impact.
+  /You may test your Stripe\.js integration over HTTP/,
+  // i18next's HTTP backend fails to load namespace files under Vite dev's
+  // `@fs/` URLs; the app falls back to embedded English copy and tests
+  // still pass functional assertions.
+  /i18next::backendConnector: loading namespace/,
+  // scarfTracking.firePixel() is invoked from a router effect on the first
+  // route render, before the useScarfTracking hook has called
+  // setScarfConfig(). Harmless (the pixel is a no-op on first call) but
+  // worth a follow-up to reorder init. See utils/scarfTracking.ts.
+  /\[scarfTracking\] firePixel\(\) called before setScarfConfig/,
+
+  // ── Vite dev-server flakiness under parallel-worker load ────────────────
+  // The next block suppresses the entire cascade that follows when Vite's
+  // dev server briefly stops accepting connections (because several workers
+  // hit it simultaneously). In CI we serve a pre-built dist via
+  // `vite preview`, where none of this happens; locally the cascade is just
+  // environmental noise. None of these patterns mask production-only bugs.
+
+  // 1) Browser-level network failure for an unreachable URL.
+  /Failed to load resource: net::ERR_/,
+  // 2) Vite's lazy chunk loader sees the network failure and throws.
+  /Failed to fetch dynamically imported module/,
+  // 3) PDF.js / pdfium WASM streaming fetch trips on the same outage.
+  /WebAssembly compilation aborted: Network error/,
+  /wasm streaming compile failed/,
+  /failed to asynchronously prepare wasm/,
+  /falling back to ArrayBuffer instantiation/,
+  // 4) React-dom logs its own wrapper line when the lazy chunk error reaches
+  //    a Suspense / ErrorBoundary. Suppress only this exact wrapper — real
+  //    React errors that aren't chunk-load failures still surface elsewhere.
+  /The above error occurred in one of your React components/,
+  // 5) Our ErrorBoundary's componentDidCatch dumps ~15 supplementary
+  //    diagnostic lines. They are useful in prod but in tests they are
+  //    pure noise on top of whatever already failed. Match by source URL.
+  /\(https?:\/\/[^)]*\/src\/core\/components\/shared\/ErrorBoundary\.tsx:/,
+];
+
+/**
+ * Per-page collector for console errors / warnings / uncaught page errors.
+ *
+ * The fixture installs one of these on every page. Messages that aren't
+ * absorbed by an active `expectConsoleError` / `suppressConsoleErrors`
+ * scope are reported in fixture teardown and fail the test.
+ */
+class ConsoleErrorRecorder {
+  private readonly failed: string[] = [];
+  private readonly scopes: Array<{ pattern: RegExp; matched: boolean }> = [];
+
+  record(text: string): void {
+    for (const pattern of GLOBAL_IGNORE_PATTERNS) {
+      if (pattern.test(text)) return; // documented global noise
+    }
+    for (const scope of this.scopes) {
+      if (scope.pattern.test(text)) {
+        scope.matched = true;
+        return; // absorbed by an active scope, not a failure
+      }
+    }
+    this.failed.push(text);
+  }
+
+  async withScope<T>(
+    pattern: RegExp,
+    fn: () => Promise<T>,
+    requireMatch: boolean,
+  ): Promise<T> {
+    const scope = { pattern, matched: false };
+    this.scopes.push(scope);
+    try {
+      const result = await fn();
+      if (requireMatch && !scope.matched) {
+        throw new Error(
+          `expectConsoleError: no console error/warning matched ${pattern} ` +
+            `during the scoped action`,
+        );
+      }
+      return result;
+    } finally {
+      const idx = this.scopes.indexOf(scope);
+      if (idx >= 0) this.scopes.splice(idx, 1);
+    }
+  }
+
+  failures(): string[] {
+    return this.failed;
+  }
+}
+
+const recordersByPage = new WeakMap<Page, ConsoleErrorRecorder>();
+
+function attachConsoleErrorRecorder(page: Page): ConsoleErrorRecorder {
+  const recorder = new ConsoleErrorRecorder();
+  recordersByPage.set(page, recorder);
+
+  page.on("console", (msg) => {
+    const type = msg.type();
+    if (!FAILING_CONSOLE_TYPES.has(type)) return;
+    const { url, lineNumber, columnNumber } = msg.location();
+    const where = url ? ` (${url}:${lineNumber}:${columnNumber})` : "";
+    recorder.record(`[console.${type}] ${msg.text()}${where}`);
+  });
+
+  page.on("pageerror", (err) => {
+    recorder.record(`[pageerror] ${err.message}`);
+  });
+
+  return recorder;
+}
+
+function getRecorder(page: Page, caller: string): ConsoleErrorRecorder {
+  const recorder = recordersByPage.get(page);
+  if (!recorder) {
+    throw new Error(
+      `${caller} requires the \`test\` exported from ` +
+        `\`@app/tests/helpers/test-base\` (or stub-test-base). ` +
+        `Are you importing \`test\` directly from "@playwright/test"?`,
+    );
+  }
+  return recorder;
+}
+
+/**
+ * Run `fn` and *require* at least one console error / warning / page error
+ * that matches `pattern` to occur during it. Matching messages are
+ * absorbed (they don't fail the test); if none match, this throws.
+ *
+ * Use when a test deliberately exercises an error path and the error
+ * surfaces in the console:
+ *
+ *   await expectConsoleError(page, /Validation failed/, async () => {
+ *     await page.getByRole("button", { name: "Submit" }).click();
+ *     await expect(page.getByRole("alert")).toBeVisible();
+ *   });
+ *
+ * The scope only covers messages emitted while `fn` is awaiting, so
+ * remember to `await` any UI assertion that the error has surfaced
+ * *inside* the callback rather than after it returns.
+ */
+export async function expectConsoleError<T>(
+  page: Page,
+  pattern: RegExp,
+  fn: () => Promise<T>,
+): Promise<T> {
+  return getRecorder(page, "expectConsoleError").withScope(pattern, fn, true);
+}
+
+/**
+ * Run `fn` and silently absorb any console errors / warnings / page
+ * errors matching `pattern`, without asserting that one occurred. Use
+ * sparingly — `expectConsoleError` is preferred because it also verifies
+ * the error path actually fires.
+ *
+ *   await suppressConsoleErrors(page, /MUI Grid v1 deprecated/, async () => {
+ *     await page.getByRole("button", { name: "Open settings" }).click();
+ *   });
+ */
+export async function suppressConsoleErrors<T>(
+  page: Page,
+  pattern: RegExp,
+  fn: () => Promise<T>,
+): Promise<T> {
+  return getRecorder(page, "suppressConsoleErrors").withScope(
+    pattern,
+    fn,
+    false,
+  );
+}
+
+/**
+ * Custom test fixture shared across all Playwright suites. Two things
+ * happen for every test that uses this base (directly or transitively
+ * via `stub-test-base.ts`):
+ *
+ *   1. The cookie-consent cookie is seeded before any navigation so the
+ *      `#cc-main` banner never renders and never intercepts clicks.
+ *   2. Console errors/warnings and uncaught page errors are captured.
+ *      If any unhandled message appears during the test, the fixture
+ *      throws during teardown and the test fails. Tests that legitimately
+ *      produce errors should wrap the offending step in
+ *      `expectConsoleError(page, /pattern/, async () => { ... })`.
  *
  * Usage: import { test, expect } from '@app/tests/helpers/test-base';
  */
 export const test = base.extend({
   page: async ({ page }, use) => {
+    const recorder = attachConsoleErrorRecorder(page);
+
     // Set the cookie consent cookie before any navigation so the banner
     // never appears. The cookieconsent library (orestbida/cookieconsent)
     // reads this cookie on init and skips the banner if consent exists.
@@ -29,6 +231,16 @@ export const test = base.extend({
     ]);
 
     await use(page);
+
+    const failures = recorder.failures();
+    if (failures.length > 0) {
+      throw new Error(
+        `Test produced ${failures.length} unhandled console error(s)/warning(s):\n` +
+          failures.map((m) => `  ${m}`).join("\n") +
+          `\n\nIf any of these are expected, wrap the action in ` +
+          `expectConsoleError(page, /pattern/, async () => { ... }).`,
+      );
+    }
   },
 });
 

frontend/editor/src/core/tests/stubbed/audit-log-ui.spec.ts

@@ -1,4 +1,5 @@
-import { test, expect, type Page } from "@playwright/test";
+import { test, expect } from "@app/tests/helpers/test-base";
+import type { Page } from "@playwright/test";
 import {
   bypassOnboarding,
   mockAppApis,

frontend/editor/src/core/tests/stubbed/certificate-validation.spec.ts

@@ -1,4 +1,5 @@
-import { test, expect, type Page } from "@playwright/test";
+import { test, expect } from "@app/tests/helpers/test-base";
+import type { Page } from "@playwright/test";
 import path from "path";
 
 // ---------------------------------------------------------------------------

frontend/editor/src/core/tests/stubbed/compare.spec.ts

@@ -18,7 +18,8 @@
  * The Vite dev server must be running (handled by playwright.config.ts webServer).
  */
 
-import { test, expect, type Page } from "@playwright/test";
+import { test, expect } from "@app/tests/helpers/test-base";
+import type { Page } from "@playwright/test";
 import path from "path";
 import { mockAppApis } from "@app/tests/helpers/api-stubs";
 

frontend/editor/src/core/tests/stubbed/convert.spec.ts

@@ -5,7 +5,8 @@
  * The Vite dev server must be running (handled by playwright.config.ts webServer).
  */
 
-import { test, expect, type Page } from "@playwright/test";
+import { test, expect } from "@app/tests/helpers/test-base";
+import type { Page } from "@playwright/test";
 import path from "path";
 import { mockAppApis } from "@app/tests/helpers/api-stubs";
 

frontend/editor/src/core/tests/stubbed/encrypted-pdf-unlock.spec.ts

@@ -17,7 +17,8 @@
  * unlock-all-wrong-password - all transitively covered or low-value.
  */
 
-import { test, expect, type Page } from "@playwright/test";
+import { test, expect } from "@app/tests/helpers/test-base";
+import type { Page } from "@playwright/test";
 import path from "path";
 import fs from "fs";
 import { mockAppApis } from "@app/tests/helpers/api-stubs";

frontend/editor/src/core/tests/stubbed/first-login-modal.spec.ts

@@ -1,4 +1,5 @@
-import { test, expect, type Page } from "@playwright/test";
+import { test, expect } from "@app/tests/helpers/test-base";
+import type { Page } from "@playwright/test";
 import { mockAppApis, seedCookieConsent } from "@app/tests/helpers/api-stubs";
 
 /**

frontend/editor/src/core/tests/stubbed/license-states.spec.ts

@@ -1,4 +1,5 @@
-import { test, expect, type Page } from "@playwright/test";
+import { test, expect } from "@app/tests/helpers/test-base";
+import type { Page } from "@playwright/test";
 import {
   bypassOnboarding,
   mockAppApis,

frontend/editor/src/core/tests/stubbed/premium-feature-gates.spec.ts

@@ -1,4 +1,5 @@
-import { test, expect, type Page } from "@playwright/test";
+import { test, expect } from "@app/tests/helpers/test-base";
+import type { Page } from "@playwright/test";
 import {
   bypassOnboarding,
   mockAppApis,

frontend/editor/src/core/tests/stubbed/saas-backend-smoke.spec.ts

@@ -6,7 +6,8 @@
  *   STIRLING_FLAVOR=saas ./gradlew :stirling-pdf:bootRun --args="--server.port=18083 --spring.profiles.include=dev"
  *   STIRLING_SAAS_URL=http://localhost:18083 npx playwright test --project=stubbed saas-backend-smoke
  */
-import { test, expect, request } from "@playwright/test";
+import { test, expect } from "@app/tests/helpers/test-base";
+import { request } from "@playwright/test";
 
 const SAAS_URL = process.env.STIRLING_SAAS_URL ?? "http://localhost:18083";
 

frontend/editor/src/core/tests/stubbed/teams-ui.spec.ts

@@ -1,4 +1,5 @@
-import { test, expect, type Page } from "@playwright/test";
+import { test, expect } from "@app/tests/helpers/test-base";
+import type { Page } from "@playwright/test";
 import {
   bypassOnboarding,
   mockAppApis,