title: expect(jest.fn())[.not].toHaveBeenCalled() error
body: <p>I'm using Enzyme/Jest to write a test for a function on my component that is triggered through an onClick of a material's menu icon. The function is passed as props to the component. When writing test, it gives me error on simulating click.</p>
  
  <pre><code>import React from 'react';
      import scssstyles from './ToggleSideNavComponent.scss';
      class ToggleSideNavComponent extends React.Component {
        render() {
          return (
              &lt;a
                id="toggle_sidebar_btn"
                className={scssstyles.menuIcon}
                onClick={this.props.handleSideNavToggle}
                &gt;
                &lt;i id="menu" className="material-icons menu-icon" style={{fontSize:30}}&gt;menu&lt;/i&gt;
              &lt;/a&gt;
          );
        }
      }
  
  
      module.exports = ToggleSideNavComponent;
  </code></pre>
  
  <p><strong>TEST</strong> </p>
  
  <pre><code>import expect from 'expect';
  import React from 'react';
  import {mount, shallow} from 'enzyme';
  import ToggleSideNavComponent from  './ToggleSideNavComponent';
  import sinon from 'sinon';
  
  function setup() {
      const props = {
          handleSideNavToggle: sinon.spy()
  
      };
  
      return {
          props: props,
          wrapper: shallow(&lt;ToggleSideNavComponent {...props} /&gt;) 
      };
  }
  
  describe('ToggleSideNavComponent', () =&gt; {
      it('should have menu icon', () =&gt; {
          const component = setup();
          expect(component.wrapper.find('a #menu').length).toBe(1);
  
          component.wrapper.find('#toggle_sidebar_btn #menu').simulate('click');
          expect(component.props.handleSideNavToggle).toHaveBeenCalled();
      });
  });
  </code></pre>
  
  <p><strong>error :</strong> </p>
  
  <pre><code>ToggleSideNavComponent › should have menu icon
  
      expect(jest.fn())[.not].toHaveBeenCalled()
  
      jest.fn() value must be a mock function or spy.
      Received:
        function: [Function proxy]
  
        at Object.&lt;anonymous&gt; (src/components/app/Header/NavLeftList/ToggleSideNavComponent/ToggleSideNavComponent.spec.js:25:94)
            at new Promise (&lt;anonymous&gt;)
            at &lt;anonymous&gt;
        at process._tickCallback (internal/process/next_tick.js:188:7)
  </code></pre>