Während ich den Testfall in die JEST for React-Datei schreibe, wird dieser Fehler angezeigt. Folgendes ist mein Beispielcode:

search_basr_test.js

jest.autoMockOff();
global.React = require('react/addons');
jest.setMock('../stores/browser_store.jsx');
beforeEach(function() {
    var search_bar = require('../components/search_bar.jsx');
});
var TestUtils = React.addons.TestUtils;

describe("Test", function() {
    it("should render Test", function() {
            var test = TestUtils.renderIntoDocument(<search_bar/>);
            expect(test).toBeDefined();
    });
    it("renders a list in a box with proper CSS classes", function() {
            var test = TestUtils.renderIntoDocument(<search_bar/>);
            let box = TestUtils.findRenderedDOMComponentWithTag(test, "div");
            expect(box.className).toEqual("sidebar__collapse");
    });
});

search_bar.jsx

return (
        <div>
            <div
                className='sidebar__collapse'
                onClick={this.handleClose}
            >
                <span className='fa fa-angle-left'></span>
            </div>
            <span
                className='search__clear'
                onClick={this.clearFocus}
            >
                {'Cancel'}
            </span>
}

Jemand da draußen, um mir dabei zu helfen ??