Class ObserverA

packages/core/src/__tests__/unit/lifecycle.unit.ts:402–405

    it('filters observers by group', () => {
      @lifeCycleObserver('group-a')
      class ObserverA implements LifeCycleObserver {
        async start() {}
      }

      @lifeCycleObserver('group-b')
      class ObserverB implements LifeCycleObserver {