jest+enzyme取不到节点？

Question

报错如下

 Expected value to be (using Object.is):

      1

    Received:

      0

      12 |       </IntlProvider>

      13 |     );

    > 14 |     expect(wrapper.find('.fullscreen-modal').length).toBe(1);

      15 |   });

      16 | });

      

spec.js如下

import React from 'react';

import { shallow } from 'enzyme';

import { IntlProvider } from 'react-intl';

import AllocatingModal from './allocatingModal';

describe('AllocatingModal', () => { // eslint-disable-line no-undef

  it('render', () => { // eslint-disable-line no-undef

    const wrapper = shallow(

      <IntlProvider locale="zh">

        <AllocatingModal />

      </IntlProvider>

    );

    expect(wrapper.find('.fullscreen-modal').length).toBe(1);

  });

});

jsx如下

<Modal

        maskClosable={false}

        title={title}

        width="100%"

        wrapClassName="fullscreen-modal"

        closable={false}

        visible={this.props.visible}

        footer={null}

      >

明明有 为什么取不到呢?