在对FormGroup进行更改后，如何在单元测试中触发valuesChanged observable？

import { TestBed, ComponentFixture } from '@angular/core/testing';
import { ReactiveFormsModule, FormGroup } from '@angular/forms';
import { MyComponent } from './my.component';

describe('MyComponent', () => {
  let component: MyComponent;
  let fixture: ComponentFixture<MyComponent>;
  let formGroup: FormGroup;

  beforeEach(async () => {
    await TestBed.configureTestingModule({
      imports: [ReactiveFormsModule],
      declarations: [MyComponent]
    }).compileComponents();

    fixture = TestBed.createComponent(MyComponent);
    component = fixture.componentInstance;
    formGroup = component.myFormGroup;
  });

  it('should trigger valuesChanged observable after FormGroup changes', () => {
    let valuesChangedTriggered = false;
    let changedValues: any;

    component.valuesChanged.subscribe((values: any) => {
      valuesChangedTriggered = true;
      changedValues = values;
    });

    // Modify the FormGroup
    formGroup.patchValue({ name: 'John' });

    // Perform the test action, e.g., submit the form
    component.onSubmit();

    // Wait for async operations to complete
    fixture.detectChanges();
    fixture.whenStable().then(() => {
      // Assert that valuesChanged observable was triggered
      expect(valuesChangedTriggered).toBe(true);

      // Assert the changed values
      expect(changedValues).toEqual({ name: 'John' });
    });
  });
});