Class HiddenTestCmp

packages/forms/signals/test/web/form_field.spec.ts:5009–5019

    }

    @Component({
      template: ` <my-input [formField]="f" /> `,
      imports: [CustomInput, FormField],
    })
    class HiddenTestCmp {
      myInput = viewChild.required<CustomInput>(CustomInput);
      data = signal('');
      f = form(this.data, (p) => {
        hidden(p, {when: ({value}) => value() === ''});
      });
    }

    const comp = act(() => TestBed.createComponent(HiddenTestCmp)).componentInstance;
    expect(comp.myInput().hidden()).toBe(true);