add hostname gating unit tests for runYoutubeAdDetection

Tests lock in expected behavior: allows youtube.com and subdomains,
privacy-test-pages.site and subdomains, rejects other domains.
Also adds resetYoutubeAdDetection() for test cleanup and stores
the start retry timeout so stop() can clear it properly.

Made-with: Cursor

Author: jdorweiler

injected/src/detectors/detections/youtube-ad-detection.js

@@ -59,6 +59,7 @@ export class YouTubeAdDetector {
         // Intervals and tracking
         this.pollInterval = null;
         this.rerootInterval = null;
+        this.startRetryTimeout = null;
         this.trackedVideoElement = null;
         this.lastLoggedVideoId = null;
         this.currentVideoId = null;
@@ -615,7 +616,7 @@ export class YouTubeAdDetector {
         if (!root) {
             if (attempt < 25) {
                 this.log.info(`Player root not found, retrying in 500ms (attempt ${attempt}/25)`);
-                setTimeout(() => this.start(attempt + 1), 500);
+                this.startRetryTimeout = setTimeout(() => this.start(attempt + 1), 500);
             } else {
                 this.log.info('Player root not found after 25 attempts, giving up');
             }
@@ -651,6 +652,10 @@ export class YouTubeAdDetector {
      * Stop the detector
      */
     stop() {
+        if (this.startRetryTimeout) {
+            clearTimeout(this.startRetryTimeout);
+            this.startRetryTimeout = null;
+        }
         if (this.pollInterval) {
             clearInterval(this.pollInterval);
             this.pollInterval = null;
@@ -763,3 +768,13 @@ export function runYoutubeAdDetection(config, logger, fireEvent) {
     detectorInstance.start();
     return detectorInstance.getResults();
 }
+
+/**
+ * @visibleForTesting
+ */
+export function resetYoutubeAdDetection() {
+    if (detectorInstance) {
+        detectorInstance.stop();
+        detectorInstance = null;
+    }
+}

injected/unit-test/youtube-ad-detection.js

@@ -1,4 +1,4 @@
-import { YouTubeAdDetector } from '../src/detectors/detections/youtube-ad-detection.js';
+import { YouTubeAdDetector, runYoutubeAdDetection, resetYoutubeAdDetection } from '../src/detectors/detections/youtube-ad-detection.js';
 
 const minimalConfig = {
     playerSelectors: ['#movie_player'],
@@ -151,4 +151,82 @@ describe('YouTubeAdDetector', () => {
             expect(detector.state.detections.adBlocker.showing).toBe(true);
         });
     });
+
+    describe('runYoutubeAdDetection hostname gating', () => {
+        const enabledConfig = { ...minimalConfig, state: 'enabled' };
+        const emptyResult = { detected: false, type: 'youtubeAds', results: [] };
+        let savedWindow;
+        let savedDocument;
+
+        beforeEach(() => {
+            savedWindow = globalThis.window;
+            savedDocument = globalThis.document;
+        });
+
+        afterEach(() => {
+            resetYoutubeAdDetection();
+            globalThis.window = savedWindow;
+            globalThis.document = savedDocument;
+        });
+
+        function setHostname(name) {
+            const mockDoc = { querySelector: () => null, querySelectorAll: () => [], body: null, hidden: false, readyState: 'complete' };
+            globalThis.window = /** @type {any} */ ({
+                location: { hostname: name, search: '' },
+                document: mockDoc,
+                navigator: { userActivation: { isActive: false } },
+                addEventListener: () => {},
+                performance: { now: () => 0 },
+                setTimeout: () => {},
+                setInterval: () => {},
+                URLSearchParams,
+            });
+            globalThis.document = /** @type {any} */ (mockDoc);
+        }
+
+        it('rejects other domains', () => {
+            setHostname('example.com');
+            expect(runYoutubeAdDetection(enabledConfig)).toEqual(emptyResult);
+        });
+
+        it('rejects domains containing youtube as a substring', () => {
+            setHostname('notyoutube.com');
+            expect(runYoutubeAdDetection(enabledConfig)).toEqual(emptyResult);
+        });
+
+        it('rejects localhost', () => {
+            setHostname('localhost');
+            expect(runYoutubeAdDetection(enabledConfig)).toEqual(emptyResult);
+        });
+
+        it('allows youtube.com', () => {
+            setHostname('youtube.com');
+            const result = runYoutubeAdDetection(enabledConfig);
+            expect(result).not.toEqual(emptyResult);
+        });
+
+        it('allows www.youtube.com', () => {
+            setHostname('www.youtube.com');
+            const result = runYoutubeAdDetection(enabledConfig);
+            expect(result).not.toEqual(emptyResult);
+        });
+
+        it('allows m.youtube.com', () => {
+            setHostname('m.youtube.com');
+            const result = runYoutubeAdDetection(enabledConfig);
+            expect(result).not.toEqual(emptyResult);
+        });
+
+        it('allows privacy-test-pages.site', () => {
+            setHostname('privacy-test-pages.site');
+            const result = runYoutubeAdDetection(enabledConfig);
+            expect(result).not.toEqual(emptyResult);
+        });
+
+        it('allows subdomains of privacy-test-pages.site', () => {
+            setHostname('test.privacy-test-pages.site');
+            const result = runYoutubeAdDetection(enabledConfig);
+            expect(result).not.toEqual(emptyResult);
+        });
+    });
 });