Function expectStatusChangeEvent

packages/forms/test/reactive_integration_spec.ts:1188–1197

(
      event: ControlEvent<T> | undefined,
      status: FormControlStatus,
      sourceControl: AbstractControl,
    )

    }

    function expectStatusChangeEvent<T>(
      event: ControlEvent<T> | undefined,
      status: FormControlStatus,
      sourceControl: AbstractControl,
    ) {
      const touchedEvent = event as StatusChangeEvent;
      expect(touchedEvent).toBeInstanceOf(StatusChangeEvent);
      expect(touchedEvent.source).toBe(sourceControl);
      expect(touchedEvent.status).toBe(status);
    }

    it('Single level Control should emit changes for itself', () => {
      const fc = new FormControl<string | null>('foo', Validators.required);