M-029 Pass 3 batch A: T-1 page tests for 5 simpler pages — XSS hardening

Pass 3 of M-029 ships per-page render + XSS-hardening test suites for the

14 T-1-deferred pages. Each test:

  - Renders the page with mock data containing <script> payloads in every

    text-rendering field.

  - Asserts no live <script data-xss='...'> element attached to the DOM.

  - Asserts no global side-effect from the script body executed (window

    __xss_pwned__ stays undefined).

  - Asserts the literal payload text appears as escaped content (proving

    the page surfaces the data without rendering it as HTML).

Batch A: 5 simpler pages (display-only / single-mutation / login).

Test files added:

  - DigestPage.test.tsx           preview HTML payload + render coverage

  - LoginPage.test.tsx            useAuth.error payload + form invariants

                                   (mocked AuthProvider via Layout.test pattern)

  - ShortLivedPage.test.tsx       cert subject DN / SAN / id / environment

                                   payloads through the DataTable rendering

  - AuditPage.test.tsx            audit-event action / actor / resource_*

                                   payloads through the DataTable rendering

  - ObservabilityPage.test.tsx    health.status + Prometheus text payloads

                                   through the <pre> rendering surface

Closes 5 of 14 T-1-deferred pages toward M-029 Pass 3 completion.

web/src/pages/ObservabilityPage.test.tsx

@@ -0,0 +1,98 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import { render, screen, waitFor, cleanup } from '@testing-library/react';
+import { QueryClient, QueryClientProvider } from '@tanstack/react-query';
+import { MemoryRouter } from 'react-router-dom';
+import type { ReactNode } from 'react';
+
+// -----------------------------------------------------------------------------
+// M-029 Pass 3 (Audit M-026): ObservabilityPage XSS-hardening + render coverage.
+//
+// ObservabilityPage renders server health + metrics. The Prometheus text
+// payload (getPrometheusMetrics) is operator-facing free-form text; the
+// existing implementation renders it inside a controlled <pre>{text}</pre>
+// surface, which React's text-interpolation escapes automatically. This test
+// pins that contract so a future refactor that switched to
+// dangerouslySetInnerHTML for "rich" rendering wouldn't slip past CI.
+//
+// Pins:
+//   1. Page renders.
+//   2. health.status / metrics fields containing literal <script> payloads
+//      do NOT execute.
+//   3. The literal payload text appears as escaped content.
+// -----------------------------------------------------------------------------
+
+vi.mock('../api/client', () => ({
+  getMetrics: vi.fn(),
+  getPrometheusMetrics: vi.fn(),
+  getHealth: vi.fn(),
+}));
+
+import ObservabilityPage from './ObservabilityPage';
+import * as client from '../api/client';
+
+function renderWithQuery(ui: ReactNode) {
+  const qc = new QueryClient({
+    defaultOptions: { queries: { retry: false, gcTime: 0, staleTime: 0 } },
+  });
+  return render(
+    <QueryClientProvider client={qc}>
+      <MemoryRouter>{ui}</MemoryRouter>
+    </QueryClientProvider>,
+  );
+}
+
+const xssPayload = '<script data-xss="observability">window.__xss_pwned__=1;</script>';
+
+describe('ObservabilityPage — render + XSS hardening (M-026 / M-029 Pass 3)', () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+    cleanup();
+    delete (window as unknown as { __xss_pwned__?: number }).__xss_pwned__;
+  });
+
+  it('renders the page header when metrics + health resolve', async () => {
+    vi.mocked(client.getMetrics).mockResolvedValue({
+      uptime: { uptime_seconds: 3600, server_started: new Date().toISOString() },
+    } as never);
+    vi.mocked(client.getHealth).mockResolvedValue({ status: 'ok' } as never);
+    vi.mocked(client.getPrometheusMetrics).mockResolvedValue('# HELP up The current up state\nup 1\n' as never);
+
+    renderWithQuery(<ObservabilityPage />);
+    await waitFor(() => {
+      expect(screen.getByText('Observability')).toBeInTheDocument();
+    });
+  });
+
+  it('does NOT execute <script> payloads in health.status / Prometheus text', async () => {
+    vi.mocked(client.getMetrics).mockResolvedValue({
+      uptime: { uptime_seconds: 3600, server_started: new Date().toISOString() },
+    } as never);
+    vi.mocked(client.getHealth).mockResolvedValue({ status: xssPayload } as never);
+    vi.mocked(client.getPrometheusMetrics).mockResolvedValue(xssPayload as never);
+
+    renderWithQuery(<ObservabilityPage />);
+    await waitFor(() => {
+      expect(screen.getByText('Observability')).toBeInTheDocument();
+    });
+
+    const liveScripts = document.querySelectorAll('script[data-xss="observability"]');
+    expect(liveScripts.length, 'observability data must not inject a live <script>').toBe(0);
+    expect(
+      (window as unknown as { __xss_pwned__?: number }).__xss_pwned__,
+      'observability <script> body must not have executed',
+    ).toBeUndefined();
+  });
+
+  it('renders the literal Prometheus payload as escaped text', async () => {
+    vi.mocked(client.getMetrics).mockResolvedValue({
+      uptime: { uptime_seconds: 3600, server_started: new Date().toISOString() },
+    } as never);
+    vi.mocked(client.getHealth).mockResolvedValue({ status: 'ok' } as never);
+    vi.mocked(client.getPrometheusMetrics).mockResolvedValue(xssPayload as never);
+
+    renderWithQuery(<ObservabilityPage />);
+    await waitFor(() => {
+      expect(document.body.textContent ?? '').toContain('<script data-xss="observability">');
+    });
+  });
+});