title: Wrapper.instance() is not a function
body: <p>I am running a test at the moment and these 2 lines are missing on my coverage</p>
  
  <pre><code>hideAddViewModal = () =&gt; {
    this.setState({showAddViewModal: false})
  }
  </code></pre>
  
  <p>I wrote the following test, but not sure why is not picking up.
  Am I missing anything? 
  Mounting my component using Enzyme and Jest</p>
  
  <pre><code>it ('Test hideAddViewModal method ',() =&gt; {
    wrapper.setState({
     showAddViewModal: false,
    });
    wrapper.update();
    expect(wrapper.instance().hideAddViewModal('test')).toEqual()
    expect(wrapper.state('hideAddViewModal')).toBeFalsy();
  });
  </code></pre>
  
  <blockquote>
    <p>Error:  wrapper.instance(...).hideAddViewModal is not a function</p>
  </blockquote>