TypeError: wrapper.exists is not a function && TypeError: wrapper.find is not a function

I am writing test cases for one of my component which is having router.and i am getting error wrapper.find is not a function. Basic requirement is need to check the existence of tag in my render,also check the aria-label attribute of tag

const Component = () => const WrappedComponent = withRouter(Component)

  describe('Error Boundary...', () => {
    it('should render children when no error is encountered', () => {
      const wrapper = ReactTestRenderer.create(
        <Router><WrappedComponent /></Router>
      );
      expect(wrapper.toJSON().type).toEqual('div');
      expect(wrapper.toJSON()find('a').attr('aria-label')).toEqual('Hello World');
    });
  });