Revert "test: rewrite tests that test zone.js implementation details"

This reverts commit de01346.

src/cdk/a11y/focus-monitor/focus-monitor.spec.ts

@@ -1,7 +1,7 @@
 import {TAB} from '@angular/cdk/keycodes';
 import {Platform} from '@angular/cdk/platform';
 import {DOCUMENT} from '@angular/common';
-import {Component, ViewChild, provideZoneChangeDetection} from '@angular/core';
+import {Component, ViewChild} from '@angular/core';
 import {ComponentFixture, TestBed, fakeAsync, flush, inject, tick} from '@angular/core/testing';
 import {By} from '@angular/platform-browser';
 import {
@@ -34,7 +34,6 @@ describe('FocusMonitor', () => {
     TestBed.configureTestingModule({
       imports: [A11yModule, PlainButton],
       providers: [
-        provideZoneChangeDetection(),
         {
           provide: DOCUMENT,
           useFactory: () => {
@@ -900,25 +899,6 @@ describe('FocusMonitor input label detection', () => {
   }));
 });
 
-describe('cdkMonitorFocus with change detection counter', () => {
-  beforeEach(() => {
-    TestBed.configureTestingModule({
-      imports: [A11yModule, ButtonWithCDCounter],
-      providers: [{provide: Platform, useValue: {isBrowser: true}}],
-    }).compileComponents();
-  });
-
-  it('should detect changes caused by focus change', async () => {
-    const fixture = TestBed.createComponent(ButtonWithCDCounter);
-    fixture.autoDetectChanges();
-    const buttonElement = fixture.nativeElement.querySelector('button');
-    buttonElement.focus();
-    await fixture.whenStable();
-    const focusChangeCounter = fixture.nativeElement.querySelector('.focus-change-counter');
-    expect(focusChangeCounter.innerText).toBe('1');
-  });
-});
-
 @Component({
   template: `<div class="parent"><button>focus me!</button></div>`,
   standalone: true,
@@ -981,15 +961,3 @@ class CheckboxWithLabel {}
 class ExportedFocusMonitor {
   @ViewChild('exportedDir') exportedDirRef: CdkMonitorFocus;
 }
-
-@Component({
-  template: `
-    <button cdkMonitorElementFocus (cdkFocusChange)="focusChangeCount = focusChangeCount + 1"></button>
-    <div class="focus-change-counter">{{focusChangeCount}}</div>
-  `,
-  standalone: true,
-  imports: [A11yModule],
-})
-class ButtonWithCDCounter {
-  focusChangeCount = 0;
-}

src/cdk/a11y/focus-monitor/focus-monitor.zone.spec.ts

@@ -0,0 +1,47 @@
+import {Platform} from '@angular/cdk/platform';
+import {patchElementFocus} from '@angular/cdk/testing/private';
+import {Component, NgZone, provideZoneChangeDetection} from '@angular/core';
+import {ComponentFixture, TestBed, fakeAsync, inject, tick} from '@angular/core/testing';
+import {A11yModule} from '../a11y-module';
+import {FocusMonitor} from './focus-monitor';
+
+describe('FocusMonitor observable stream Zone.js integration', () => {
+  let fixture: ComponentFixture<PlainButton>;
+  let buttonElement: HTMLElement;
+  let focusMonitor: FocusMonitor;
+  let fakePlatform: Platform;
+
+  beforeEach(() => {
+    fakePlatform = {isBrowser: true} as Platform;
+    TestBed.configureTestingModule({
+      imports: [A11yModule, PlainButton],
+      providers: [{provide: Platform, useValue: fakePlatform}, provideZoneChangeDetection()],
+    }).compileComponents();
+  });
+
+  beforeEach(inject([FocusMonitor], (fm: FocusMonitor) => {
+    fixture = TestBed.createComponent(PlainButton);
+    focusMonitor = fm;
+    fixture.detectChanges();
+    buttonElement = fixture.debugElement.nativeElement.querySelector('button');
+    patchElementFocus(buttonElement);
+  }));
+
+  it('should emit inside the NgZone', fakeAsync(() => {
+    const spy = jasmine.createSpy('zone spy');
+    focusMonitor.monitor(buttonElement).subscribe(() => spy(NgZone.isInAngularZone()));
+    expect(spy).not.toHaveBeenCalled();
+
+    buttonElement.focus();
+    fixture.detectChanges();
+    tick();
+    expect(spy).toHaveBeenCalledWith(true);
+  }));
+});
+
+@Component({
+  template: `<div class="parent"><button>focus me!</button></div>`,
+  standalone: true,
+  imports: [A11yModule],
+})
+class PlainButton {}