diff --git a/packages/devtools/src/__tests__/cd-diagnosis-real.test.ts b/packages/devtools/src/__tests__/cd-diagnosis-real.test.ts
index 827be14a..17553b0d 100644
--- a/packages/devtools/src/__tests__/cd-diagnosis-real.test.ts
+++ b/packages/devtools/src/__tests__/cd-diagnosis-real.test.ts
@@ -2,12 +2,12 @@
 import '@angular/compiler';
 import * as core from '@angular/core';
 import { Component } from '@angular/core';
-import { afterEach, describe, expect, it } from 'vitest';
+import { setPostSignalSetFn } from '@angular/core/primitives/signals';
+import { afterEach, describe, expect, it, vi } from 'vitest';
 import { attachChangeDetection, type CdReport } from '../cd-overlay.ts';
 import { findCdScheduler } from '../cd-diagnosis.ts';
 import { angularAtLeast, bootstrapRoot, STANDALONE, type BootedApp } from './angular-version.ts';
 
-const wait = (ms: number) => new Promise((resolve) => setTimeout(resolve, ms));
 const ngOf = () => (globalThis as { ng?: unknown }).ng;
 const supported = angularAtLeast('20.0');
 const signal = <T>(value: T, debugName: string) =>
@@ -78,6 +78,13 @@ Component({
     <app-counter></app-counter>`,
 })(Shell);
 
+/** Whether a signal write hook is set, such as the one a recording adds once its import resolves. */
+function hasSignalWriteHook(): boolean {
+  const hook = setPostSignalSetFn(null);
+  setPostSignalSetFn(hook);
+  return hook !== null;
+}
+
 function fakeRpc() {
   const handlers = new Map<string, (...args: unknown[]) => unknown>();
   const reports: CdReport[] = [];
@@ -110,13 +117,13 @@ describe.skipIf(!supported)('change detection diagnosis with a real app', () =>
     document.body.innerHTML = '<app-root></app-root>';
     app = await bootstrapRoot(Shell);
     app.appRef.tick();
-    await wait(20);
+    await app.appRef.whenStable();
     const { my, handlers, reports } = fakeRpc();
     const cd = attachChangeDetection(my, 'p1', ngOf, 50);
     stop = cd.stop;
     handlers.get('change-detection-record')!({ pageId: 'p1', on: true });
     // The signal write hook loads with a dynamic import.
-    await wait(20);
+    await vi.waitFor(() => expect(hasSignalWriteHook()).toBe(true), { timeout: 3000 });
     return {
       async report() {
         await cd.push(true);
@@ -135,7 +142,7 @@ describe.skipIf(!supported)('change detection diagnosis with a real app', () =>
   it('credits a click to its event, target and listener component, with the signal it wrote', async () => {
     const recording = await record();
     (document.querySelector('app-counter button') as HTMLButtonElement).click();
-    await wait(40);
+    await app!.appRef.whenStable();
     const report = await recording.report();
     const cycle = report.cycles.find((c) => c.cause?.kind === 'event');
     expect(cycle?.cause).toMatchObject({
@@ -154,8 +161,14 @@ describe.skipIf(!supported)('change detection diagnosis with a real app', () =>
     const counter = (ngOf() as { getComponent(el: Element): Counter }).getComponent(
       document.querySelector('app-counter')!,
     );
-    setTimeout(() => counter.bump(), 0);
-    await wait(60);
+    await new Promise<void>((resolve) =>
+      setTimeout(() => {
+        counter.bump();
+        resolve();
+      }, 0),
+    );
+    // The write schedules a tick, which Angular tracks as a pending task.
+    await app!.appRef.whenStable();
     const report = await recording.report();
     const cause = report.cycles.find((c) => c.cause?.signal === 'count')?.cause;
     expect(cause?.kind).toBe('signal');
@@ -168,7 +181,7 @@ describe.skipIf(!supported)('change detection diagnosis with a real app', () =>
     const recording = await record();
     for (let i = 0; i < 3; i++) {
       (document.getElementById('add') as HTMLButtonElement).click();
-      await wait(40);
+      await app!.appRef.whenStable();
     }
     const report = await recording.report();
     const diagnosis = report.diagnosis!;
diff --git a/packages/devtools/src/__tests__/page-highlight.test.ts b/packages/devtools/src/__tests__/page-highlight.test.ts
index 7903bae9..3bf79f9c 100644
--- a/packages/devtools/src/__tests__/page-highlight.test.ts
+++ b/packages/devtools/src/__tests__/page-highlight.test.ts
@@ -1,5 +1,8 @@
 // @vitest-environment jsdom
 import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+// Loaded with the file, not inside a test: its module graph takes seconds to
+// transform, which would count against that test's timeout.
+import { initOverlay } from '../overlay.ts';
 import {
   clearHighlight,
   HIGHLIGHT_SAFETY_MS,
@@ -118,9 +121,10 @@ describe('page highlight', () => {
 
   it('keeps a panel highlight until a clear arrives, and an agent highlight clears itself', async () => {
     vi.stubGlobal('BroadcastChannel', undefined);
-    const { initOverlay } = await import('../overlay.ts');
     const stop = await initOverlay();
-    vi.useFakeTimers();
+    // Only the clear timers are under test. A faked requestAnimationFrame would
+    // replay the box's follow loop every 16 ms over the minute advanced below.
+    vi.useFakeTimers({ toFake: ['setTimeout', 'clearTimeout'] });
     try {
       document.body.innerHTML = '<app-card class="card"></app-card>';
       place(document.querySelector('app-card')!, { x: 1, y: 2, width: 3, height: 4 });
@@ -148,7 +152,6 @@ describe('page highlight', () => {
 
   it('accepts an SVG element from the highlight-in-page request', async () => {
     vi.stubGlobal('BroadcastChannel', undefined);
-    const { initOverlay } = await import('../overlay.ts');
     const stop = await initOverlay();
     try {
       document.body.innerHTML = '<svg><g class="bar"></g></svg>';