Embed font hoping that this will make the visual tests reproducible

docs/PLAYWRIGHT_DESIGN.md

@@ -131,7 +131,7 @@ This section defines the granular step-by-step instructions and enumerates **eve
 *   **`tests/global.d.ts`**
     *   *Rationale:* Custom global type declaration file for E2E tests to safely declare `__registeredTools` on the `Window` interface without TypeScript compiler warnings. Redundant overrides for `Navigator` are omitted because the test suite inherits it from the application's core WebMCP declarations.
 *   **`tests/helpers.ts`**
-    *   *Rationale:* Shared test utilities to encapsulate wildcard route mocking for family tree fetching (`setupGedcomRoute`) and tracking interception (`blockTracking`). This avoids code duplication across spec files.
+    *   *Rationale:* Shared test utilities to encapsulate wildcard route mocking for family tree fetching (`setupGedcomRoute`) and hermetic context routing (`setupHermeticEnvironment`). This avoids code duplication across spec files.
 *   **`tests/fixtures/embedded_frame.html`**
     *   *Rationale:* Physical template wrapper file defining the iframe and message-passing structure for embedded view E2E verification.
 *   **`src/datasource/testdata/test.ged`**
@@ -190,7 +190,7 @@ This section defines the granular step-by-step instructions and enumerates **eve
 3. Author `tests/global.d.ts` to provide TypeScript type definitions for mocked window objects:
    * **Type Extension**: Declares `__registeredTools?` on the global `Window` interface to prevent TypeScript compilation errors during WebMCP mocks.
 4. Author `tests/helpers.ts` to provide reusable mock setups and routing interceptions:
-   * **Tracking Blockers**: Implements a `blockTracking(context)` helper that intercepts and aborts requests targeting Google Analytics and Tag Manager (`**/*google-analytics.com/**`, `**/*googletagmanager.com/**`) to guarantee hermetic and fast test execution.
+   * **Hermetic Routing**: Implements a `setupHermeticEnvironment(context)` helper that intercepts tracking services (`**/*google-analytics.com/**`, `**/*googletagmanager.com/**`) and embeds baseline web fonts to guarantee deterministic and fast test execution.
    * **GEDCOM Mocks**: Implements a `setupGedcomRoute(context)` helper that reads the version-controlled local dataset (`src/datasource/testdata/test.ged`) and routes all requests matching `**/family.ged` to be fulfilled with it, serving a `200 OK` response with CORS enablement headers (`Access-Control-Allow-Origin: *`).
 5. Author the physical template wrapper file `tests/fixtures/embedded_frame.html` for testing embedded iframe communications:
    * **Structure**: Defines a standard wrapper document housing an iframe that points to the app's embedded route: `/#/view?embedded=true&handleCors=false`.
@@ -200,7 +200,7 @@ This section defines the granular step-by-step instructions and enumerates **eve
 
 ##### 1. Intro Test (`tests/intro.spec.ts`)
 Checks the landing page layout, menu items, and basic static DOM presence:
-* **Setup**: Leverages `beforeEach` to block analytics and tracking servers using the `blockTracking` helper, then loads the index page (`/`).
+* **Setup**: Leverages `beforeEach` to configure hermetic routes using the `setupHermeticEnvironment` helper, then loads the index page (`/`).
 * **Assertions**:
   * Verifies that the main intro landing text content (specifically checking for the presence of `'Examples'`) is visible on the page.
   * Asserts that core action buttons in the menu (exact text `'Open file'` and `'Load from URL'`) are properly rendered and visible to the user.

docs/SCREENSHOT_TESTS_DESIGN.md

@@ -51,7 +51,7 @@ This section defines the granular, step-by-step implementation steps and enumera
 #### 2. Files to [NEW]
 
 *   **`tests/helpers.ts`**
-    *   *Rationale:* Provide shared E2E/visual testing helper utilities. Features `blockTracking()` to abort external Google Analytics and Google Tag Manager network requests (ensuring offline hermetic execution) and `setupGedcomRoute()` to serve a standard mock `.ged` dataset.
+    *   *Rationale:* Provide shared E2E/visual testing helper utilities. Features `setupHermeticEnvironment()` to abort external tracking requests and embed local fonts (ensuring offline hermetic execution) and `setupGedcomRoute()` to serve a standard mock `.ged` dataset.
 *   **`tests/intro_visual.spec.ts`**
     *   *Rationale:* Verify the landing page layout, copy block positions, and logo alignments. Employs an in-browser DOM script to overwrite dynamic footer versioning and dynamic changelog blocks prior to capture, ensuring baseline immunity.
 *   **`tests/charts_visual.spec.ts`**
@@ -74,7 +74,7 @@ This section defines the granular, step-by-step implementation steps and enumera
    * `"test:visual:update": "playwright test --project=visual --update-snapshots"` to automatically regenerate baseline reference files.
 
 #### Step 2: Landing Page Visual Validation Spec (`tests/intro_visual.spec.ts`)
-1. Define a test block marked with the `@visual` tag, utilizing `blockTracking` helper in `beforeEach`.
+1. Define a test block marked with the `@visual` tag, utilizing `setupHermeticEnvironment` helper in `beforeEach`.
 2. Instruct the browser to navigate to the root path `/`.
 3. Right before assertion, trigger `page.evaluate` to clean dynamic elements:
    * Target the `.version` class element and set `.innerText = "version: 2026-01-01 00:00 (testcommit)"`.
@@ -91,7 +91,7 @@ This section defines the granular, step-by-step implementation steps and enumera
    * Capture the isolated canvas screenshot: `expect(container).toHaveScreenshot('chart-[type].png')`.
 
 #### Step 4: Details Panel Layouts Spec (`tests/details_visual.spec.ts`)
-1. Set up a `beforeEach` block to block analytics via `blockTracking(context)`.
+1. Set up a `beforeEach` block to establish hermetic routes via `setupHermeticEnvironment(context)`.
 2. Define isolated test blocks with the `@visual` tag, each loading its own dedicated inline micro-GEDCOM dataset:
    * **Complex Names Test:**
      * Mock `**/family.ged` with a GEDCOM string containing prefix/suffix/rufname tags.

tests/README.md

@@ -38,7 +38,7 @@ To enable lightweight, reproducible, and offline executions, tests rely on the f
 *   **[fixtures/embedded_frame.html](fixtures/embedded_frame.html)**: HTML template for serving cross-origin iframe wrapper mockups virtually to the browser container.
 *   **[global.d.ts](global.d.ts)**: TypeScript declarations defining window overrides (like AI registration pointers `window.__registeredTools`) to bypass compiler warnings.
 *   **[helpers.ts](helpers.ts)**: Unified routing utilities:
-    *   `blockTracking()`: Intercepts and halts metrics and analytical HTTP queries during spec executions.
+    *   `setupHermeticEnvironment()`: Intercepts and halts metrics/analytical queries and embeds local baseline fonts during spec executions.
     *   `setupGedcomRoute()`: Re-routes standard genealogy payload network paths directly to load standard local datasets on-the-fly (`src/datasource/testdata/test.ged`).
 *   **[tsconfig.json](tsconfig.json)**: Typecheck preferences custom to the Playwright runner environment to avoid compilation type collisions.
 *   **`[spec_name]-snapshots/`**: Directory structure containing expected baseline references and image comparison files.

tests/details_visual.spec.ts

@@ -1,11 +1,11 @@
 import {expect, test} from '@playwright/test';
 import dedent from 'dedent';
 import * as fs from 'fs';
-import {blockTracking, mockGedcomResponse, waitForFonts} from './helpers';
+import {mockGedcomResponse, setupHermeticEnvironment, waitForFonts} from './helpers';
 
 test.describe('Details panel visual validation @visual', () => {
   test.beforeEach(async ({page, context}) => {
-    await blockTracking(context);
+    await setupHermeticEnvironment(context);
     await page.goto('/');
     await waitForFonts(page);
   });

tests/helpers.ts

@@ -2,12 +2,49 @@ import {BrowserContext, Page} from '@playwright/test';
 import * as fs from 'fs';
 
 /**
- * Blocks external tracking services (like Google Analytics and Google Tag Manager)
- * to guarantee a hermetic and fast test environment.
+ * Sets up a hermetic test environment by blocking external tracking services
+ * and intercepting Google Fonts to serve static embedded fonts locally.
  */
-export async function blockTracking(context: BrowserContext): Promise<void> {
+export async function setupHermeticEnvironment(context: BrowserContext): Promise<void> {
   await context.route('**/*google-analytics.com/**', (route) => route.abort());
   await context.route('**/*googletagmanager.com/**', (route) => route.abort());
+
+  // Intercept Google Fonts stylesheet requests to serve a deterministically embedded local font.
+  await context.route('**/fonts.googleapis.com/css2**', async (route) => {
+    const cssContent = `
+      @font-face {
+        font-family: 'Montserrat';
+        font-style: normal;
+        font-weight: 100 900;
+        font-display: block;
+        src: url('http://localhost:3000/test-fonts/montserrat.woff2') format('woff2');
+      }
+      @font-face {
+        font-family: 'Montserrat';
+        font-style: italic;
+        font-weight: 100 900;
+        font-display: block;
+        src: url('http://localhost:3000/test-fonts/montserrat.woff2') format('woff2');
+      }
+    `;
+    await route.fulfill({
+      status: 200,
+      contentType: 'text/css',
+      headers: {'Access-Control-Allow-Origin': '*'},
+      body: cssContent,
+    });
+  });
+
+  // Intercept requests for the locally embedded test font and serve the static binary.
+  await context.route('**/test-fonts/montserrat.woff2', async (route) => {
+    const fontBuffer = fs.readFileSync('tests/fixtures/montserrat.woff2');
+    await route.fulfill({
+      status: 200,
+      contentType: 'font/woff2',
+      headers: {'Access-Control-Allow-Origin': '*'},
+      body: fontBuffer,
+    });
+  });
 }
 
 /**
@@ -38,7 +75,7 @@ export async function setupGedcomRoute(context: BrowserContext): Promise<void> {
   );
 
   await mockGedcomResponse(context, gedcomContent);
-  await blockTracking(context);
+  await setupHermeticEnvironment(context);
 }
 
 /**

tests/intro.spec.ts

@@ -1,9 +1,9 @@
 import {expect, test} from '@playwright/test';
-import {blockTracking} from './helpers';
+import {setupHermeticEnvironment} from './helpers';
 
 test.describe('Intro page', () => {
   test.beforeEach(async ({page, context}) => {
-    await blockTracking(context);
+    await setupHermeticEnvironment(context);
     await page.goto('/');
   });
 

tests/intro_visual.spec.ts

@@ -1,9 +1,9 @@
 import {expect, test} from '@playwright/test';
-import {blockTracking, waitForFonts} from './helpers';
+import {setupHermeticEnvironment, waitForFonts} from './helpers';
 
 test.describe('Intro page visual validation @visual', () => {
   test.beforeEach(async ({page, context}) => {
-    await blockTracking(context);
+    await setupHermeticEnvironment(context);
     await page.goto('/');
     await waitForFonts(page);
   });