如何使用React Jest测试TextField Material-UI元素？

我使用React和Material-UI构建了一个组件。我正在使用React和Redux。

我的index.jsx看起来像这样：

import React from 'react';
import { render } from 'react-dom';
import { Provider } from 'react-redux';
import MuiThemeProvider from 'material-ui/styles/MuiThemeProvider';
import configureStore from '../store/configureStore';
import Routes from '../routes/routes';
import '../styles/main.less';

const store = configureStore();
render(
  <Provider store={store}>
    <MuiThemeProvider>
      <Routes />
    </MuiThemeProvider>
  </Provider>,
  document.getElementById('app'),
);

我的组件InputSearch看起来像这样：

import React, { PropTypes, Component } from 'react';
import TextField from 'material-ui/TextField';

class InputSearch extends Component {
  ...

  render() {
    return (
      ...
      <TextField
        defaultValue={this.props.keyword}
        ref={(input) => { this.input = input; }}
        autoFocus
        hintText='Type a keyword'
        errorText={this.state.errorText}
        floatingLabelText='Search for keyword'
        style={styles.textField}
      />
    );
  }
}

InputSearch.propTypes = {
  keyword: PropTypes.string.isRequired,
  resetSearch: PropTypes.func.isRequired,
  searchBooks: PropTypes.func.isRequired,
  toggleResultsOpacity: PropTypes.func.isRequired,
  firstSearch: PropTypes.bool.isRequired,
};

export default InputSearch;

我正在使用Airbnb酶和Jest进行单元测试。我对该InputSearch组件的测试如下所示：

import React from 'react';
import { shallow, mount } from 'enzyme';
import MuiThemeProvider from 'material-ui/styles/MuiThemeProvider';
import TextField from 'material-ui/TextField';
import InputSearch from '../components/InputSearch/InputSearch';

const resetSearchMock = jest.fn();
const searchBooksMock = jest.fn();
const toggleResultsOpacityMock = jest.fn();

const setup = () => {
  const props = {
    keyword: '',
    resetSearch: resetSearchMock,
    searchBooks: searchBooksMock,
    toggleResultsOpacity: toggleResultsOpacityMock,
    firstSearch: true,
  };

  const wrapper = shallow(<MuiThemeProvider><InputSearch {...props} /></MuiThemeProvider>);

  return {
    props,
    wrapper,
  };
};

describe('Initial test', () => {
  test('Shows error message when input search is empty.', () => {
    const { wrapper, props } = setup();
    expect(wrapper.find(TextField).getValue()).toEqual('');
  });
}

但是，出现以下错误：

TypeError: wrapper.find(...).getValue is not a function

有人可以帮助我找到正确的方法来检查Material UI的值TextField吗？