当组件didmount中有函数调用时,酶挂载失败

我有一个react组件,其中有一个click函数,如下所示:

    clickTwitter(e) {

    e.stopPropagation();
    let storyId = this.refs.storyToTweet.getAttribute('id');
    if (storyId != undefined) {
        let storyIdValue = this.props.storyId;
        this.postOnTwitter(storyIdValue);
    }
}

在组件didmount中,我有以下内容:

    componentDidMount(){
    this.fbInit();
}

fbInit(){
    return facebookInitializer= function(d, s, id) {
        var js, fjs = d.getElementsByTagName(s)[0];
        if (d.getElementById(id)) return;
        js = d.createElement(s); js.id = id;
        js.src = `https://connect.facebook.net/en_US/sdk.js#xfbml=1&version=v2.12&appId=${FACEBOOK.appId}&autoLogAppEvents=1`;
        fjs.parentNode.insertBefore(js, fjs);
    }(document, 'script', 'facebook-jssdk');

}

我有以下测试用例:

        it('should call the clickTwitter method once', () => {
        // creates the spy for the clickTwitter method
        let clickTwitterSpy = sinon.spy(StoryMedia.prototype, 'clickTwitter');
        let props={

        }
        // wraps the component by using the enzyme mount method
        const wrapper = mount(<StoryMedia/>);

        // simulates a user clicking the twitter button
        wrapper.find('.shareTwitterDummy').simulate('click');
        // asserts that the clickTwitter method was called once when the button was clicked
        assert.strictEqual(StoryMedia.prototype.clickTwitter.calledOnce, true);
        // restores the method to its original state
        clickTwitterSpy.restore();
    });

当我运行测试时,会出现以下奇怪的错误:

TypeError: Cannot read property 'parentNode' of undefined....

如果我从componentDidMount中删除this.fbInit();一切正常。 我能告诉测试忽略this.fbinit()吗?或者任何其他的解决方案