Class NoOpValidator

packages/forms/test/reactive_integration_spec.ts:4122–4139

        let registerOnAsyncValidatorChangeFired = 0;

        @Directive({
          selector: '[ng-noop-validator]',
          providers: [
            {provide: NG_VALIDATORS, useExisting: forwardRef(() => NoOpValidator), multi: true},
          ],
          standalone: false,
        })
        class NoOpValidator implements Validator {
          @Input() validatorInput = '';

          validate(c: AbstractControl) {
            return null;
          }

          public registerOnValidatorChange(fn: () => void) {
            registerOnValidatorChangeFired++;
          }
        }

        @Directive({
          selector: '[ng-noop-async-validator]',