Method check

packages/core/test/acceptance/change_detection_spec.ts:898–904

(h: string)

            }

            check(h: string) {
              if (h === hook) {
                this.count++;
                if (this.count > 1) throw new Error(`ng${hook} should be called only once!`);
                this.parentComp.triggerChangeDetection();
              }
            }
          }

          TestBed.configureTestingModule({declarations: [ParentComp, ChildComp]});